吾識計maths f(x)(07會考MC)....請列出計算步驟...吾該~~~~~~

55. Let f(x) be a polynomial. If f(x) is divisible by x - 1, which of the following must be a factor of f(2x+1)
A. x [By remainder theorem, f(1) = 0. f(2x+1) = f(1) → 2x+1 = 1 → x = 0, so x - 0 = x is a factor of f(2x+1).]
B. x-3
C. 2x-1
D. 2x+1