Refer to the Provided Supply and Demand Graph of Product

Multiple Choice

Refer to the provided supply and demand graph of Product X. If there are positive externalities from the consumption of Product X, then the socially optimal demand curve would be

A) to the left of the D curve on the graph.
B) to the right of the D curve on the graph.
C) at the position of the D curve on the graph.
D) an upward-sloping line.