What is the term for the option in which the insurer retains the dividend to be invested?

The correct term for the option in which the insurer retains the dividend to be invested is known as Accumulation at Interest. This option allows the insurer to hold the dividends and invest them, typically earning interest on the accumulated amount. This can benefit the policyholder, as the dividends can grow over time, increasing the overall value of the policy when the policyholder chooses to access them later.

The other options provided refer to different concepts. An Accumulation Period usually refers to the timeframe during which premiums are paid and cash value accumulates in a life insurance policy. An Additional Monthly Benefit does not apply in this context, as it relates to supplementary benefits provided in certain policies. Adjustable Life is a specific type of life insurance policy that allows flexibility in premium and coverage amounts, but it does not pertain to how dividends are handled.