A small team of Croatian spelunkers recently discovered

Official Explanation

Answer E - A vertical scan reveals the two choices "as deep as" and "deeper than". The phrase "as deep as" implies equality, while the phrase "deeper than" implies inequality. Here the sentence needs to express inequality, so we immediately eliminate (A), (B) and (C). Also (B) adds the word "supposed" which is illogical here. The record is not for the world's deepest hole – it's for the world's deepest known hole. Therefore we cannot qualify the previous record-holder by using the word "supposed". The previous record-holder was unquestionably the world's deepest known hole at the time. Choice (C) inserts the word "any" which is unnecessary and does nothing to improve the sentence.

The only difference between (D) and (E) is "any" versus "the". As stated above, the word "any" does not improve this sentence. While it is true that the new hole is over 200 feet deeper than any previous record-holder, this fact logically follows from the fact that the new hole is over 200 feet deeper than the previous record-holder, so the word "any" does not provide any further clarity, and in fact introduces a redundancy. Therefore we eliminate (D), leaving (E) as the correct answer choice.