Ans: D
$\begin{array}{rcl}
hx + (x-3)^2 & \equiv & x^2 +10x + k \\
hx + x^2 -6x +9 & \equiv & x^2+10x+k \\
x^2 + (h-6)x + 9 & \equiv & x^2 +10x + k
\end{array}$
$\begin{array}{rcl}
hx + (x-3)^2 & \equiv & x^2 +10x + k \\
hx + x^2 -6x +9 & \equiv & x^2+10x+k \\
x^2 + (h-6)x + 9 & \equiv & x^2 +10x + k
\end{array}$
By comparing the coefficients of both sides, we have
$\left\{ \begin{array}{l}
h-6 = 10 \\
9 = k
\end{array} \right.$
Hence, we have
$\left\{ \begin{array}{l}
h=16 \\
k=9
\end{array} \right.$
