Which sentence demonstrates correct use of the apostrophe? a) the bicycle is definitely theirs'. b) her's is the last drawing of its kind. c) a dollars' worth is not what it used to be. d) the dangerous crosswalk is everybody's problem.

The correct answer is choice D: The dangerous crosswalk is everybody's problem. ...In choice A, the word "theirs" is not a contraction, so it would not need an apostrophe. The same is true for choice B: "Hers" is not a contraction; no apostrophe is needed. Also, in choice C, "dollar's" is not a contraction, but it is a possessive, so it needs an apostrophe, however the apostrophe is incorrectly placed after the "s", instead of before it.