The correct answer is A. Insurer.
In a fixed benefit annuity, the insurer promises to pay the annuitant a fixed amount of money for the rest of their life. The insurer bears the investment risk, meaning that if the investments don’t perform well, the insurer will still have to pay the annuitant the promised amount.
In a variable annuity, the annuitant bears the investment risk. The annuitant chooses how to invest their money, and the amount of money they receive in retirement will depend on the performance of those investments.
A state is a government entity that has the power to tax and regulate businesses. A risk pool is a group of people who share the risk of loss.
I hope this helps!