One Method of Reducing the Moral Hazard Problem in Health

One method of reducing the moral hazard problem in health care insurance would be

A) for all insurance companies to increase the cost for coverage.
B) to allow insurance companies to agree to cover preventive care completely.
C) to allow insurance companies to impose payment limits on preventable conditions.
D) to allow insurance companies to limit the number of new customers.
E) to allow insurance companies to require a medical exam before offering coverage.