California on Thursday became the latest state to announce huge cash prizes to incentivize vaccination against the coronavirus, offering $116.5 million in giveaways ? many smaller payments as well as a final drawing for 10 winners of $1.5 million each.

As rates of vaccination slow, more state and local leaders are getting creative to boost an urgent effort to protect Americans from covid-19 and get communities back to normal. Some incentives are more modest: free fries, bouquets or alcohol. (Louisiana, for instance, recently debuted "shots for shots.") But Ohio Gov. Mike DeWine (R) upped the ante this month when he announced a multimillion-dollar lottery. Soon, other states followed suit.

Some have questioned the strategy's cost-effectiveness, and one reporter asked Gov. Gavin Newsom (D) at a Thursday news conference whether he ever thought California would have to spend so much to get people to get free vaccinations against a deadly disease.

"The cost of not getting vaccinated is exponentially, incalculably higher," Newsom said.

question -

In the current situation, the COVID19 vaccine supplier is almost in a monopoly position. According to economic theory on monopoly producers, the monopoly producer will restrict the quantity of output in order to maximize its profit.

Assuming the demand curve D is the marginal social benefit curve, please use the concept of allocative efficient to identify the efficient equilibrium quantity and discuss how, according to your opinion, the efficient equilibrium quantity can be realised.

(5 marks for a good explanation and 5 marks for a correct diagram.)