Why Did Congress Expand TriCare to Cover Medicare Gaps but Not

Why did Congress expand TriCare to cover Medicare gaps but not apply increased coverage to elderly Americans not in the military?

A) Congress felt it was necessary in order to address the issue of increased numbers of wounded soldiers coming back from Iraq and Afghanistan.
B) The increased coverage of TriCare was just a pilot program in preparation for a larger, national increase.
C) Congress actually did expand Medicare coverage for all Americans while also expanding TriCare.
D) It was a politically attractive move in an election year, and a national increase in coverage was deemed too costly.