The solutions to a quadratic equation are $x=2$ and $x=7$. If $k$ is a nonzero constant, which of the following must be equal to the quadratic equation?

A$k(x-2)(x-7)=0$

B$(x+2)(x+7)+k=0$

C$(x-2)(x-7)+k=0$

D$k(x+2)(x+7)=0$