Use the Following Figure to Answer the Question : Figure

Multiple Choice

Use the following figure to answer the question : Figure 20-1 : D₁ and S₁ are the private demand and supply curves,of a commodity produced by a competitive firm.S₂ reflects the social marginal cost of production,while S₀ represents the external marginal cost.
-According to Figure 20-1,the efficient output is ______ than the equilibrium output by _____ units.

A) more;400
B) less;400
C) more;100
D) less;200