Suppose That $M U _ { x } = 10$ And $M U _ { y } = 20$

Multiple Choice

Suppose that $M U _ { x } = 10$ and $M U _ { y } = 20$ . Further suppose that the consumer's budget constraint can be expressed as $20 x + 10 y = 400$ . For this consumer, the optimal amount of good $x$ to buy would be:

A) 5 .
B) 0 .
C) $20 .$
D) 40 .