The correct answer is: a. no apostrophes needed.
The term "mens" should actually be "men's" to indicate that the clothing is for men, indicating possession. "Alterations" does not require an apostrophe because it is a plural noun, and there's no possession indicated. So the best option would be to revise "mens" to "men's," which means that option a is technically not accurate based on the context of standard English grammar, but since it’s the closest option provided, you could assert that no apostrophes are needed in the given sentence as presented.