Which of the following is a common exclusion in health insurance policies?

Pre-existing conditions are commonly excluded in health insurance policies due to the potential for higher costs associated with individuals who have existing health issues before acquiring the policy. Insurers often include this exclusion to mitigate the risk of financial loss when providing coverage. This means that if a person already has a health condition when they apply for insurance, the insurer may not cover treatments or services related to that condition for a specified period or may deny coverage altogether.

The other choices typically represent services that are included or generally provided under many health insurance plans. Emergency services, preventive care, and prescription drugs are commonly covered benefits, as insurers recognize their importance in maintaining overall health and managing medical expenses. Hence, these options are not typically excluded.