Suppose That the Marginal Private Benefit of a New Vaccine

Multiple Choice

Suppose that the marginal private benefit of a new vaccine could be measured as Suppose that the marginal social benefit could be measured as Suppose that the private marginal cost curve could be measured as What amount of a per-unit subsidy would encourage the optimal societal consumption of the vaccine?

A) $1.
B) $2.
C) $4.
D) $6.