GMAT Critical Reasoning (CR) | Re: Politician: Of the candidates running, Thompson is the best person

Why A and not B

Politician: Of the candidates running, Thompson is the best person to lead this nation. For one thing, Thompson opposes higher taxes whereas the other candidates support them. Many would agree that anyone who opposes higher taxes will make a better leader than someone who supports them.

Which one of the following, if true, casts the most doubt on the politician's argument?

(A) Opposing higher taxes is not a factor contributing to good leadership.

(B) Being opposed to higher