Answer:
The answer is: A) Mary Jane has a comparative advantage in law so she should specialize in law and hire a carpenter to make her cabinets.
Explanation:
Mary Jane has a comparative advantage by working as a lawyer over working as a carpenter. As a lawyer she can earn $150 an hour.
Considering that Mary Jane is 3 times as fast as a good carpenter, her work as a carpenter could be valued as the combined work of three carpenters. But even three carpenters earn less than a lawyer; $60 an hour ($20 an hour per carpenter times 3 carpenters).
So Mary Jane definitely should work as a lawyer and hire a carpenter or even three carpenters to build her cabinets.