Explanation

When you start to tackle a TC question for the GRE exam during your practice routine OR during your real exam the thing does not change, at all: you first and primary goal is to follow a clear strategy.

• Divide the sentence, especially the longest one, into chunks. Sentence by sentence. Analyze them with a brief brainstorming on the real meaning of these sentence on its own and in context, as a whole.
• Doing so, scanning incessantly and immediately, faster than a lightning, for clues scattered here and there along the entire statement in front of you.
  Grasp the overall meaning. Do not waste time hovering a single word. Understand the BIG picture. After all, a Caravaggio's painting is beautiful in its entirety, even though the particulars are amazing and punch you in the face like a fist from nowhere, so much they have beauty.
  Do not be intimidated by the length of sentence or because is convoluted. Do not try to digest in one breath. Dissect it and move slowly but with determination, at an atomic level. Aggressive.

So, let move on and see what the first sentence brings us.

The question of (i) _________ in photography has lately become nontrivial.

Not a long sentence. The issue, the matter, the question related to something at stake, in this case, the photography world, lately surged as really important. Not so much to reflect on. Not so many clues, if no one. Move one. For now, scanning the 3 first blanks is a waste of time. Do not bother even to read them. We are just at the beginning.

Prices for vintage prints (those made by a photographer soon after he or she made the negative) so drastically (ii) _________ in the 1990s that one of those photographs might fetch a hundred times as much as a nonvintage print of the same image.

Wow, that is a long sentence and I already pretty sure it has a lot, but a lot of information. it sounds like a stretch but believe me, it is not

keep in mind that we are talking about photography and that the matter became important.

The vintage prints (follow a brief but clear explanation of them and what they are) so drastically (ii) ______ that during the '90s a photograph can make a bunch of money. I.E if someone with a nonvintage photo earned $ 1, those who sold vintage photos could make $10 or $100 or $1000, we do not know. What we do know is that we have a difference, huge or not is irrelevant, but we do have a difference.

As I announced to you: we do have a lot of information.

What is quite clear is that we do have a difference in the prices of the photos: vintage vs nonvintage. This is a key concept because it is pivotal to tackle the forthcoming blanks.

ballooned If you do not know about this word, think about the balloon. It is inflated by air or gas. Or even think to the Zeppelin aircraft. In the end, it was an immense balloon. From this is fairly easy to associate the ballon (inflated) and the prices that skyrocketed - and the difference in prices. I am quite sure we have already found our suitable blank.

Of course, always look at the other answer choices. This is mandatory. We must be 100% sure of our answer. Not 99%.

weakened Ther are not so many words to spend on this word. It is completely out of scope. here we do not have any clue about something weak.

varied this word says to me anything about. yeah, sure we do have a variation in the prices but this is not the exact meaning of the sentence. The real reason is that who made vintage photos gained a lot of money in regard to who made nonvintage photos. It is different from the concept of variation.

It was perhaps only a matter of time before someone took advantage of the (iii) ________ to peddle newly created "vintage" prints for profit.

before or after someone really smart took advantage of that situation, making money. This is the essence of the sentence.

so, what do we know so far ?? we know that a photographer could make a lot of money thanks to the vintage photos. And we do also know that someone else took advantage of this because it was a good way to make easy money (maybe).

ambiguity and duplicity. I take a look at these two words at the same time because once I have a clear idea of what is going on, these two words are out of context, immediately. Ambiguity means uncertain and duplicity means of two faces. a duplicate, a second copy or a tenth of copies.

Soon or after someone will exploit the discrepancy between vintage and nonvintage photos. Very easy to pick the right one under this light.

Now back to the first blank, everything should be easy. After all, we have tackle probably the two difficult blanks among the three.

The question of (i) _________ in photography has lately become nontrivial.

At this point, looking at the answer choice should be easy.

forgery I do not know the exact meaning of this word, forgery makes me think about a place where something is made, craftsmanship. We talked about creating vintage photos vs nonvintage. This must be the answer, no matter what.

Influence and style In the entire sentence we did not have any clue about the influence of the photos, I do not know, upon the society at large. Nor the style of the photos. We talked about making money.

A, D, and G are the correct answers.

Down below, you could read a succinct yet good explanation provided by me.