Carcass I feel the usage of 'inexperienced enough to adopt' here is slightly confusing. They must be inexperienced enough to adopt a great spending policies. Can you explain the usage of such sentences?

Hi sir

I did not get frankly. do you mean the blank inserted is not clear? or the sentence as a whole or part of the sentence or BOTH?

In my opinion, inexperienced enough to adopt = did not adopt. So, the answers should be did not adopt "a miserly or a stringent" policy and because of this, it exhausted its erstwhile surplus

Both of you are looking only at the sentence fragment "the fledgling company was inexperienced enough to adopt __________ spending policy" and it can give such a meaning as you have suggested.

But you have to take the full sentence into account and when you do that - especially the final sentence fragment "and it quickly exhausted its erstwhile surplus." - the official answer is the correct one.

Sentence Equivalence demands that you take the full sentence into account and choose the words to get two sentences that are identical in meaning. It is necessary to read and understand the entire sentence fully.

This is not the case with Text Completion, where you can focus on just a fragment of a sentence and still get the correct answer. However, it is always better to read and understand the full sentence if you can.