AHSME 1960 Problem 20

The coefficient of $x^7$ in the expansion of $\left(\frac{x^2}{2}-\frac{2}{x}\right)^8$ is: $\textbf{(A)}\ 56 \textbf{(B)}\ -56 \textbf{(C)}\ 14 \textbf{(D)}\ -14 \textbf{(E)}\ 0$