How Does a Per-Unit Subsidy Affect the Simple Monopoly Equilibrium

Multiple Choice

How does a per-unit subsidy affect the simple monopoly equilibrium?

A) The subsidy does not affect marginal cost and thus does not affect the monopoly equilibrium.
B) The subsidy lowers the price charged by the monopoly,but it also lowers social gain.
C) The subsidy increases the monopoly's profit but does not improve social gain.
D) The subsidy causes both monopoly output and social gain to increase.