Which of the following is NOT an optional health insurance policy provision?

Proof of loss is considered a standard provision in health insurance policies rather than an optional one. It is a fundamental requirement for making a claim in which the insured must provide evidence of the loss incurred in order to receive benefits under the policy.

On the other hand, misstatement of age, illegal occupation, and earnings to insurance are typically optional provisions that may be included at the discretion of the insurer or the policyholder. These provisions offer specific guidelines on how the insurer will handle situations such as misrepresentation of age, activities that are considered dangerous or illegal, and rules regarding the insured's income as it pertains to benefits. By being optional, these provisions allow for a certain degree of customization in the policy based on the needs of the insured and the underwriting criteria of the insurer.