Cosmo Worked on a Difficult Calculus Problem for Several Hours

Multiple Choice

Cosmo worked on a difficult calculus problem for several hours to no avail. He decided to take a break from his labors by taking a bath. Midway through his bath, he jumped up and shouted, "Eureka, I solved the problem!" He then ran to his desk and made the calculations. Cosmo allowed __________ to help him overcome the __________ that impeded solution.

A) incubation; mental sets
B) a rest period; functional fixedness
C) insight; mental sets
D) incubation; functional fixedness