Suppose That in Blue City Each Year, 50 Rock Concerts

Suppose that in Blue City each year, 50 rock concerts and 30 opera concerts take place. If the Blue City entertainment czar (someone having great power or authority) decides to schedule 49 rock concerts and 31 opera concerts next year, about 65% of the population will approve, 25% will disapprove, and 10% won't care. This indicates that:

A) output efficiency requires an equal number of rock and opera concerts.
B) it would be a Pareto improvement to schedule one more opera concert at the expense of a rock concert.
C) it would not be a Pareto improvement to schedule one more opera concert at the expense of a rock concert.
D) input efficiency requires an equal number of rock and opera concerts.