What is defined as a contract between an insurance company and a policyholder?

The correct choice is medical insurance, as it specifically refers to a contract between an insurance company and a policyholder that provides coverage for medical expenses. This type of insurance helps individuals manage the high costs associated with healthcare services, such as hospital visits, doctor consultations, and treatments. The policyholder pays premiums to the insurance company, which in turn agrees to cover certain medical costs as outlined in the policy.

Other options, while related to aspects of insurance, do not fit the definition as precisely. A health plan generally describes a broader set of health benefits and services provided to members, which may include medical insurance, but is not limited to it. Life insurance specifically provides financial coverage in the event of the policyholder's death, and accident insurance offers coverage for injuries that result directly from accidents. While all these terms relate to insurance, medical insurance is uniquely characterized by its focus on health-related expenses, making it the most accurate choice for the question asked.