Moral hazard: refers to the fact that after a certain contract is signed, the agent carries out activities in the case where the client cannot monitor or the cost exceeds the benefits of supervision, and this kind of activities will cause losses to the client. According to the above definition, which of the following behaviors is not a moral hazard? ['A terminally ill person conceals his illness and purchases a huge amount of life insurance.', 'People who buy car-theft insurance are reluctant to install car anti-theft devices.', 'People who buy property insurance are reluctant to spend money to strengthen door locks.', 'People who purchase health insurance visit hospitals more often than before.']