Final answer:
The policy summary and buyer's guide must be given to the applicant at the time of policy delivery.
Step-by-step explanation:
The correct answer is D. At the time of policy delivery.
According to the National Association of Insurance Commissioners (NAIC), a policy summary and buyer's guide must be provided to the applicant at the time of policy delivery. This ensures that the applicant has all the necessary information about the policy before finalizing the purchase.
Providing the policy summary and buyer's guide at the time of application (option A) or within a certain period of policy issuance (options B and C) would not be sufficient as the applicant would not have the opportunity to review these documents and make an informed decision before obtaining the policy.