math多項式問題

polynomial f(x) is divisible by x-2 gives that f(2)=0
If f(X-2) is divisible by something, f(a-2)=0, a is a real number.
For f(2)=0, f(a-2)=0 if and only if a-2=2, a=4
therefore, the answer is b

我轉一轉做中文,
f(x)可以比x-2除盡,當f(x-2)可以比咩除盡
以上的式中f(x)轉左做f(x-2),即=x-2
因f(x)可以比x-2除盡,所以,f(x-2)可以比x-2-2除盡
即f(x-2)可以比x-4除盡,所以答案=b