Solve the Problem $z$ For an Industrial Country Was Estimated As $z=x^{8} y^{7}$

Multiple Choice

Solve the problem.
-The production function $z$ for an industrial country was estimated as $z=x^{8} y^{7}$ , where $x$ is the amount of labor and $y$ the amount of capital. Find the marginal productivity of capital.

A) $16 x^{7} y^{7}$
B) $14 x^{8} y^{6}$
C) $7 x^{8} y^{6}$
D) $8 x^{7} y^{7}$