The Table Below Shows a Competitive Firm's Short-Run Production Function $\begin{array}{cccc} \text {Units of Labor } & \text { Units of Output} \\3 &370\\4 &490\\5 &570\\6 &600\\7&620\\\end{array}$

The table below shows a competitive firm's short-run production function.Labor is the firm's only variable input,and market price for the firm's product is $2 per unit. $\begin{array}{cccc} \text {Units of Labor } & \text { Units of Output} \\3 &370\\4 &490\\5 &570\\6 &600\\7&620\\\end{array}$

If the wage rate is $200,how many units of labor will the firm employ?

A) 3
B) 4
C) 5
D) 6
E) 0,the firm shuts down