The Figure Given Below Shows the Demand and Cost Curves

The figure given below shows the demand and cost curves of a perfectly competitive firm. Figure: 9.4
D: Demand curve
MC: Marginal cost curve
ATC: Average-total cost curve
AVC: Average-variable-cost curve
-Refer to Figure 9.4.The presence of the average-variable-cost curve suggests that the firm is operating:

A) in the short run.
B) in the long run.
C) at a gain.
D) in a monopoly.
E) at a zero profit.