Which of the Following Best Describes Eligibility Criteria for Medicare

Which of the following best describes eligibility criteria for Medicare?

A) any American older than age 65 is eligible
B) only people older than age 65 are eligible, and only if they have worked at least 40 credits
C) various populations are eligible, including those 65 years and older with 10 years of eligible employment, younger persons on SSDI for at least 2 years, and persons with specific disabling conditions
D) at any age, individuals are only eligible for Medicare after they have developed a disability