What is the primary purpose of a medical insurance contract?

The primary purpose of a medical insurance contract is to reimburse a percentage of medical bills incurred by the policyholder. This structure is designed to help manage the financial risks associated with healthcare costs. By reimbursing a portion of expenses, medical insurance allows individuals to seek necessary medical care without bearing the entire financial burden, which can be prohibitively expensive.

This kind of coverage typically involves cost-sharing between the insurance provider and the policyholder, where the insurer pays a predetermined percentage of the medical expenses after the policyholder has met their deductible. This arrangement encourages the insured to utilize healthcare services while also keeping insurance premiums manageable.

In contrast, the other options suggest scenarios that do not align with the fundamental nature of health insurance. Full coverage for all expenses or the payment of 100% of the policyholder's expenses would not be sustainable for insurance companies, as it would result in excessive costs across the board. Additionally, offering only preventative care services is a limited approach that does not encompass the broad scope of medical services that policyholders may need throughout their lives. Thus, the focus on reimbursement aligns with the operational model of health insurance, making it the correct answer.