Ashley Is an Attorney and Also an Excellent Typist

Ashley is an attorney and also an excellent typist. She can type 120 words per minute, but she charges attorney fees at $100 per hour. Benjamin would like some typing work but can only type 60 words per minute. According to the law of comparative advantage, Ashley should hire Benjamin to do her typing if and only if his wage rate is less than

A) $10 per hour.
B) $50 per hour.
C) $60 per hour.
D) $100 per hour.