South Africa joined the Commonwealth as the 51st member on 2 May 1994. The Commonwealth is a voluntary association of 54 independent countries, most of which were formerly part of the British Empire. South Africa was a member of the Commonwealth from 1931 to 1961, when it was expelled for its apartheid policies. It rejoined the Commonwealth in 1994 after the end of apartheid.
Option A: May 1993 is incorrect. South Africa did not join the Commonwealth in May 1993.
Option B: May 1994 is correct. South Africa joined the Commonwealth on 2 May 1994.
Option C: May 1995 is incorrect. South Africa did not join the Commonwealth in May 1995.
Option D: May 1996 is incorrect. South Africa did not join the Commonwealth in May 1996.