Marginal Revenue Equals Marginal Cost at an Output of 20

Multiple Choice

Marginal revenue equals marginal cost at an output of 20 units. At this output, marginal revenue equals $20, average variable cost equals $15, and average total cost equals $25. In the short run, a profit-maximizing firm will earn a profit of

A) -$200.
B) -$100.
C) $200.
D) $400.