Solve
-The Effective Yield from a Grove of Miniature Pear $\mathrm { E } = x ( 800 - x )$

Multiple Choice

Solve.
-The effective yield from a grove of miniature pear trees is described by the equation $\mathrm { E } = x ( 800 - x )$ , where $x$ is the number of pear trees per acre. What is the maximum effective yield? How many pear trees per acre should be planted to achieve the maximum yield?

A) Maximum yield $= 160,000$
number of trees per acre planted $= 800$
B) Maximum yield $= 160,000$
number of trees per acre planted $= 400$
C) Maximum yield $= 160,000$
number of trees per acre planted $= 200$
D) Maximum yield $= 40,000$
number of trees per acre planted $= 200$