42 U.S.C. § 1395o. Eligible individuals

Every individual who—

1. (1)
   (1)is entitled to hospital insurance benefits under part A, or
2. (2)
   (2)has attained age 65 and is a resident of the United States, and is either (A) a citizen or (B) an alien lawfully admitted for permanent residence who has resided in the United States continuously during the 5 years immediately preceding the month in which he applies for enrollment under this part,