Question

Claim: hybrid vehicles help eliminate air pollution

Answer 1

Straw man fallacy happens when you falsely argue against the similar proposition proposed by your opponent and by this way you claim opponent's proposition to be wrong. Observing the options we'll see that A is not correct because there is a claim against people, not the proposition. Option C and D could be true or they could be claimed true. Indeed, they based on facts. Only in option B, we can observe a false counterclaim against the initial proposition.    

Answer 2

Option B. "Forcing people to buy hybrid vehicles is wrong" is a counterclaim that makes a straw man fallacy.

A straw man fallacy occurs when an argument refutes a point that the opposing side did not make. A straw man fallacy does not discuss the original argument but instead argues against another, "fake" argument that exaggerates an issue.

Option A. is a personal attack. Options C. and D. could conceivably be counterpoints to the original argument. 

However, Option B. is refuting an argument the original statement is not making. The original argument says only the hybrids help eliminate air pollution. No one said anything about forcing people to buy them -- this is an exaggerated claim. Therefore, Option B. is a straw man fallacy.