Answer: (A)
Efficiency deals with the size of the economic pie, and equality deals with how fairly the pie is sliced.
Step-by-step explanation:
According to Gregory Mankiw, resources are scarce and therefore every society must use its scarce resources to derive as much benefits as it can. It is this derived benefits he calls the "economic pie"
The more efficient a society is, the more the benefits (or the larger the economic pie) it can derive from its resources.
According to Mankiw, equality means fairness in distributing the benefits (or slicing the pie) among the people in that society.