There Are Three Consumers of a Public Good; Their Marginal

Multiple Choice

There are three consumers of a public good; their marginal benefits are given by:
Consumer 1: MB = 400 - Q
Consumer 2: MB = 200 - 2Q
Consumer 3: MB = 600 - Q
Where Q is the quantity of the public good. The marginal cost of the public good is MC = 600 + 296Q. What is the socially optimal quantity?

A) 6
B) 2
C) 3
D) 1