At the Current Level of Output, a Profit-Maximising Firm in a Competitive

At the current level of output, a profit-maximising firm in a competitive market earns average revenue of $20 and has an average total cost of $17. Suppose that the firm's marginal cost curve is equal to its average total cost curve at an output level of 50 units. How much profit is earned by the firm at its current level of output?

A) more than $150
B) exactly $150
C) less than $150
D) none of the above is necessarily correct