Solve the Problem $p$ And the Quantity $x$ Sold of a Certain Product Obey the Demand Equation

Multiple Choice

Solve the problem.
-The price $p$ and the quantity $x$ sold of a certain product obey the demand equation
$$p = - \frac { 1 } { 6 } x + 200 , \quad 0 \leq x \leq 1,200 \text {. }$$
What quantity $x$ maximizes revenue? What is the maximum revenue?

A) $600 ; \$ 60,000$
B) $900 ; \$ 45,000$
C) $300 ; \$ 45,000$
D) 1, $200 ; \$ 60,000$