Which one of the following is not a permanent member of the U.N. Security Council?

The correct answer is (c) Japan.

The five permanent members of the United Nations Security Council are China, France, Russia, the United Kingdom, and the United States. These five countries were the victors of World War II and were given permanent seats on the Security Council as a result.

Japan is not a permanent member of the Security Council, but it is a non-permanent member for the term 2023-2024.