Say whether each of the following scenarios describes an insurance problem caused by adverse selection or by moral hazard.
a. People who have homeowners insurance are less likely than others to replace the batteries in their smoke detectors.
b. People who enjoy dangerous hobbies are more likely than others to buy life insurance.
c. People whose parents died young are more likely than others to enroll in health insurance.
d. People who have liability coverage on their car insurance take less care than others to avoid accidents.