Final answer:
An insurer is required to explain its reasons for denying coverage under the ERISA law.
Step-by-step explanation:
Under the law, an insurer is required to explain its reasons for denying coverage under the ERISA (Employee Retirement Income Security Act). ERISA is a federal law that sets standards for pension plans and health benefit plans provided by employers. It requires insurers to provide participants with specific information about their plans, including the reasons for denial of coverage.