An insurer decides to sell annuities in a state and prices the annuities based on the average mortality rates by age and sex in that state. After some years, it finds that it is losing money because the people who buy the annuities are much healthier than average and so live a very long time, while the people who do not buy are much sicker than average. This is best described as an example of:

a. Adverse selection

b. Moral hazard

c. Uninsurable risk

d. Specific hazard

e. Correlated risk