What term refers to a person asserting a right to payment under an insurance policy?

The correct term for a person asserting a right to payment under an insurance policy is "first party claimant." This term specifically refers to the individual who holds the policy or has a direct relationship with the insurance company and is seeking to receive benefits or compensation for a loss covered by the policy. In this context, a first-party claimant is typically the insured party who is making a claim directly against their own insurance coverage.

The other options are distinct in their meanings: a third party claimant refers to someone who makes a claim against the insurance policy of another party, often in the context of liability insurance. An insured is a general term for the person covered by an insurance policy but does not specifically indicate that they are currently making a claim. Lastly, a beneficiary is someone named to receive benefits from a policy in the event of the insured's death or other specified occurrence, but they do not directly assert a right to payment in the same way that a first party claimant does.