Answer:
Point C and G. Refer to the attached image.
Step-by-step explanation:
According to the attached image, the price and quantity combination the government would regulate this firm to get as close as possible to the most efficient point for society is C and G because, this is the point where marginal cost MC and Average Total Cost intercept and form lower equilibrium point.
This means that if company sell at this point they will not run at shortage and also for buying society, the quantity they will buy is also at the increase making it the most efficient point for the society.