The Utility Function $U = f ( x , y )$

Multiple Choice

The utility function $U = f ( x , y )$ is a measure of utility (or satisfaction) derived by a person from the consumption of two products x and y. Suppose the utility function is $U = - 7 x ^ { 2 } + 5 x y - 2 y ^ { 2 }$ . Determine the marginal utility of product x.

A) $5 x - 4 y$
B) $- 14 x + 5 y$
C) $- 14 x + 5 y - 2 y ^ { 2 }$
D) $- 7 x ^ { 2 } + 5 x - 4 y$
E) $- 14 x + 5 - 4 y$