AMC 12 2001 Problem 13

The parabola with equation $y=ax^2+bx+c$ and vertex $(h,k)$ is reflected about the line $y=k$. This results in the parabola with equation $y=dx^2+ex+f$. Which of the following equals $a+b+c+d+e+f$?

$\text{(A) }2b \text{(B) }2c \text{(C) }2a+2b \text{(D) }2h \text{(E) }2k$