While James was in college, he did not have dental insurance. James went to see a dentist once a year. After James graduated and started working, he bought dental insurance for himself. This insurance is a zero co-pay, no-deductible policy, so James pays nothing for his dentist visits. In the following year, James neglected his teeth (by brushing and flossing less) and had four dentist appointments. This is an example of:

A. A market with perfect information

B. A moral hazard problem

C. An adverse-selection problem

D. A lemons problem