Of course Steve supports government sponsorship of the arts. He’s an a

Steve is X (artist) - X supports Y (government sponsorship of the arts) - so Steve supports Y

(A) Of course if a person lies to me, I will never trust that person again.
This is not based on established facts rather on a condition - Eliminate

(B) Conservatives in the past have prevented ratification of any nuclear arms limitation treaties with the Soviet Union (or Russia), so they will prevent the ratification of the current treaty.
We do not know if any behavior is typical of conservatives. We just know that conservatives have done X in the past - Eliminate

(C) Mr. Sullivan is the police commissioner, so it stands to reason that he would support the NRA’s position on gun control.
Mr.Sullivan is X (police commissioner) - X supports Y (gun control program) so Mr.Sullivan supports Y - Keep

(D) Following her conscience, Congresswoman Martinez voted against the death penalty, in spite of the fact that she knew it would doom her chances for reelection.
Completely out of line

(E) You’re in no position to criticize me for avoiding paying my fair share of taxes. You don’t even pay your employees a fair wage.
Again, completely out of line of the stem's reasoning

Answer is (C)