The beginning of the sentence attacks us with a modification error. The noun that comes after the comma after "heads" is "durability," so the grammar of the sentence conveys that durability is what has broad, flat, heads.

Applying the prediction, we look for the answer choices that dispel the problem, and those are (D) and (E). Choice (D) has a redundant construction with the word "similar," because the phrase "is to" has already set up a comparison.

The correct answer is (E).