Final answer:
A) Medicare
Workers receiving social security benefits at age sixty-five are automatically covered under Medicare Part A, designed to cover hospital and inpatient expenses for the elderly.
Step-by-step explanation:
A worker who applies for social security benefits and is receiving them at age sixty-five is automatically covered under part A of Medicare (A). This coverage is a program to pay the medical expenses of those over sixty-five, established by the Social Security Act of 1965.
Medicare Part A is the hospital insurance component of Medicare, which helps cover inpatient care in hospitals, skilled nursing facility care, hospice care, and some home health care. Workers pay a percentage of their income into Social Security and Medicare, which then provides income and health care benefits to the elderly.