Who is primarily covered by Medicare?

Medicare primarily covers individuals aged 65 and older, making this the correct answer. This federal health insurance program was established to provide coverage for the elderly, ensuring they have access to necessary medical services as they age. In addition to those aged 65 and older, Medicare can also cover certain younger individuals with disabilities or specific illnesses, such as End-Stage Renal Disease (ESRD) or Amyotrophic Lateral Sclerosis (ALS). However, the central focus of Medicare is on the senior population, which is why option B is the correct choice.

The other options do not align with the primary objectives of Medicare. Individuals with low income may qualify for Medicaid, a different program designed to assist those with financial challenges. Those with chronic illnesses may receive various forms of assistance or support, but this does not specifically implicate Medicare as their primary payer. Lastly, individuals under 18 years of age are typically not covered by Medicare, as the program is directed at older adults.