This is quite easy if you go by context instead of looking for the words in the options. Sometimes this is the best way to answer these questions. Upon reading the context, the context is obvious, its that of a new writer contending with the fact that his/her work is not as original as they thought it to be. So that gives us our first two blanks easily, the first blank is a synonym of frustrating/annoying. Only 'galling' works here. The second blank is obvious from context, it is some variation of the word 'original', only 'novel' works here.

The last blank is a bit trickier, it says that this situation is worsened when the less popular author's work is (wrongly) assumed to be a derivative because of some reason. Now if it is wrongly assumed to be derivative then it can only mean that the less popular author's work came first, i.e. it 'precedes' the more popular work. So that is what we choose. Our options are, A,D,H.

I am not getting that, [Now if it is wrongly assumed to be derivative then it can only mean that the less popular author's work came first, i.e. it 'precedes' the more popular work.] So if something is wrongly to be assumed derivative how come it will it will precede, I think so it should follow/succeed