The following question contains a sentence with a blank. Choose the most…

CONCEPT: A verb that fills a blank must pass two tests at once — (1) its meaning must fit the logic of the sentence, and (2) its collocation (the preposition or structure it pairs with) must be grammatically correct. Here the cause (rigorous training and unwavering determination) is positive and the result (remarkable success) is positive, so the verb must express a positive cause-to-result relationship and must idiomatically take the preposition “to”.

APPLICATION: “contributed to” means “helped to bring about / played a part in”. It is positive (a cause leading to a good result) and it pairs correctly with “to”. The sentence then reads: training and determination contributed to their remarkable success — i.e. they helped cause that success. This satisfies both the meaning test and the collocation test.

CONTRAST: Compare each alternative against the same two tests:

• “detracted” is negative (to take away from) and idiomatically takes “from”, not “to” — it fails both tests.

• “underestimated” means to judge something as less than it is; it states no cause-to-result link and is not used with “to” here.

• “isolated” means to set apart — separation, not a contribution toward an outcome.

• “impeded” means to hinder or obstruct — the opposite of helping success.

Only the positive, correctly-collocating verb fits both tests, so the blank is filled by contributed.