The Group of Seven (G-7) is a forum of the world’s seven most industrialized economies. G-6 was formed in 1975 by France, Germany, Italy, Japan, the United States, and the United Kingdom. Canada was invited to join this group in 1976 that eventually created the Group of Seven. In 1998, the Russian Federation (RF) was accepted by the G-7 countries as a full member, transforming G-7 into the Group of Eight (G-8). However, in 2014, Russia was suspended from G-8 after it had annexed Crimea and created tensions with Ukraine. Therefore, the correct option is D.