When a Monopolistically Competitive Firm's Demand Curve Shifts Leftward,what Happens

Multiple Choice

When a monopolistically competitive firm's demand curve shifts leftward,what happens to its marginal revenue curve?

A) Nothing, the marginal revenue curve is unchanged.
B) It disappears.
C) It shifts rightward.
D) It shifts leftward.
E) None of the above is correct because the effect on the marginal revenue curve depends on whether the demand was initially elastic or inelastic.