Which of the following UN organisations has been awarded with Nobel Prize twice?

The Office of the United Nations High Commissioner for Refugees (UNHCR) has been awarded the Nobel Peace Prize twice — in 1954 for its groundbreaking work in Europe, and again in 1981 for assisting refugees worldwide. IPCC won the Nobel Peace Prize once (2007, shared with Al Gore), IAEA won it once (2005, with Mohamed ElBaradei), and UNICEF won it once (1965). Therefore UNHCR is the correct answer.