Refer to the Following

Refer to the following:

The graph on the left shows the short-run marginal cost curve for a typical firm selling in a perfectly competitive industry. The graph on the right shows current industry demand and supply.
-If the firm's demand and marginal revenue curves were drawn in the left-hand graph, what would be the elasticity of demand?

A) zero
B) -6
C) -0.6
D) infinitely elastic
E) unitary