What characteristic defines a high-deductible health plan (HDHP)?

A high-deductible health plan (HDHP) is specifically defined by its structure of having higher deductibles and lower premiums compared to more traditional health insurance plans. This allows individuals to pay less each month for their insurance, but they are responsible for a greater share of their healthcare costs before the insurance begins to pay.

The rationale for this design is to encourage consumers to become more involved in their healthcare spending, as they will essentially be paying out-of-pocket for services until they reach the deductible limit. This can foster a sense of cost awareness regarding medical services, potentially leading to more prudent healthcare choices by the insured.

In contrast, plans with lower deductibles typically come with higher premiums, meaning that the insured pays more upfront each month but has to pay less out-of-pocket when they need care. Plans that claim to have no out-of-pocket expenses for services tend to be structured very differently and are not characteristic of HDHPs.

Thus, option C appropriately defines HDHPs with its distinction of having higher deductibles and lower monthly premiums.