Suppose That the Revenue Generated by Selling X Units of a Certain

Suppose that the revenue generated by selling x units of a certain commodity is given by $R = - \frac { 1 } { 5 } x ^ { 2 } + 600 x$ . Assume that R is in dollars. What is the maximum revenue possible in this situation?

A) $450,000
B) $440,000
C) $430,000
D) $900,000
E) $480,000