premise: The 11th (Craigavon) Battalion, Ulster Defence Regiment was formed from companies of the 2nd Battalion Ulster Defence Regiment (2 UDR) and the 3rd Battalion Ulster Defence Regiment in 1972. In 1991 under the reductions planned in Options for Change by the British Army, it again amalgamated with 2 UDR to form the 2nd/11th Battalion Ulster Defence Regiment.
hypothesis: UDR stands for user demand regulation.
reason: UDR is defined as Ulster Defence Regiment 