Final answer:
A life insurance application must be signed by the proposed insured, agent, and underwriter, but not the beneficiary.
Step-by-step explanation:
The correct answer is d) The beneficiary. A life insurance application must be signed by the proposed insured, the agent, and the underwriter. The proposed insured is the person who will be covered by the insurance policy, the agent is the person who sells the policy, and the underwriter assesses the risk and determines the premium. However, the beneficiary, who is the person or entity that will receive the insurance benefit upon the death of the insured, does not need to sign the application.