Final answer:
Active duty service members are not eligible for TRICARE Select; they must enroll in TRICARE Prime. TRICARE Select is for non-active service members like retirees. Medicare is the healthcare system for individuals primarily over the age of sixty-five.
Step-by-step explanation:
The category of beneficiaries that is not eligible for TRICARE Select is active duty service members. TRICARE Select is a self-managed, preferred provider network plan available to non-active duty members, which includes retirees, their families, and some others. Active duty service members are required to enroll in TRICARE Prime, which offers them a range of healthcare services with military or civilian providers that are part of the Prime network.
On the other hand, the public healthcare system that offers insurance primarily to people over sixty-five years old is Medicare. Medicare is a federal program that provides healthcare coverage if you are 65 or older, or under 65 and meet certain conditions. Different parts of Medicare cover specific services, but it is especially designed to cater to the healthcare needs of the elderly population, as well as younger individuals with disabilities.