I am not understanding how to answer this...

Price 0,25$,50$,75$, 100$,200$.

Quantity demanded: 300,000,275,000, 250,000, 200,000,100,000, 30,000.

Quantity Supplied: 0, 50,000, 100,000, 200,000, 300,000, 400,000

If the government does not want there to be a shortage or surplus, what price should the government allow suppliers to charge? Would it be charge 75$ as the quantity demanded and supplied are both 200,000?

What externalities exist in the market for flu shots?Use these externalities to explain why the government would sponsor (set the price at 0) for flu shots.

If a new vaccine is approved, what will happen to the equilibrium price and quantity of vaccines? Would the equilibrium price shift, and the quantity demand would increase, and supply decrease?