Marginal Revenue Equals Marginal Cost at an Output of 10

Multiple Choice

Marginal revenue equals marginal cost at an output of 10 units. At this output, marginal revenue equals $25, average variable cost equals $30, and average total cost equals $40. In the short run, a profit-maximizing firm will earn a profit of

A) -$150.
B) -$100.
C) $0.
D) $150.