Read this and answer the question. If the question is unanswerable, say "unanswerable".

With the deactivation of USS Enterprise in December 2012, the U.S. fleet comprises 10 supercarriers. The House Armed Services Seapower subcommittee on 24 July 2007, recommended seven or maybe eight new carriers (one every four years). However, the debate has deepened over budgeting for the $12–14.5 billion (plus $12 billion for development and research) for the 100,000 ton Gerald R. Ford-class carrier (estimated service 2016) compared to the smaller $2 billion 45,000 ton America-class amphibious assault ships, which are able to deploy squadrons of F-35Bs. The first of this class, USS America, is now in active service with another, USS Tripoli, under construction and 9 more are planned.

Which other carrier joins the USS America in unactive service?
unanswerable