A Firm with Two Plants,A and B,has the Following Estimated $$\begin{array} { l } Q _ { d } = 120 - 10 P \\M C _ { A } = 4 + ( 1 / 5 ) Q _ { A } \\M C _ { A } = 6 + ( 1 / 10 ) Q _ { A }\end{array}$$

Multiple Choice

A firm with two plants,A and B,has the following estimated demand and marginal cost functions: $$\begin{array} { l } Q _ { d } = 120 - 10 P \\M C _ { A } = 4 + ( 1 / 5 ) Q _ { A } \\M C _ { A } = 6 + ( 1 / 10 ) Q _ { A }\end{array}$$ In order to maximize profit,how many units of output should the firm produce?

A) 10
B) 15
C) 25
D) 45
E) 50