Which of the following is a sufficient reason for the cancellation or refusal to renew a policy?

Nonpayment of premium is a sufficient reason for the cancellation or refusal to renew a policy. In the context of insurance, timely payment of premiums is essential, as it constitutes the policyholder's agreement to maintain coverage. When a policyholder fails to pay their premium, the insurer has a legitimate basis for considering the contract void or terminating it, since the insurer relies on these payments to cover potential claims and manage risk.

On the other hand, late filing of a claim might indicate issues in the claims process but does not typically provide grounds for cancellation or non-renewal of a policy; claims can often still be evaluated based on their merits regardless of filing timing. Increased coverage needs are usually not a reason for cancellation or non-renewal; instead, they can lead to a policy revision or an endorsement to increase coverage limits. Additionally, a change of address is usually a logistical matter and does not affect the terms of the insurance contract unless the change leads to a higher risk, which would require adjustment rather than outright cancellation.

In summary, nonpayment of premium directly violates the terms of the insurance agreement, making it a clear and sufficient reason for an insurer to cancel or refuse renewal of a policy.