Which of the following organization is not the integral part of World Bank?

The World Bank Group consists of International Bank for Reconstruction and Development (IBRD), established in 1944, which provides debt financing on the basis of sovereign guarantees; International Finance Corporation (IFC), established in 1956, which provides various forms of financing without sovereign guarantees, primarily to the private sector; International Development Association (IDA), established in 1960, which provides concessional financing (interest-free loans or grants), usually with sovereign guarantees; International Centre for Settlement of Investment Disputes (ICSID), established in 1965, which works with governments to reduce investment risk; Multilateral Investment Guarantee Agency (MIGA), established in 1988, which provides insurance against certain types of risk, including political risk, primarily to the private sector.