Which of the following nation states was not a member of the Triple Entente?

France

Austria-Hungary

Russia

Britain

Austria-Hungary

Austria-Hungary was not a member of the Triple Entente.

To determine which nation state was not a member of the Triple Entente, we need to understand what the Triple Entente was. The Triple Entente, also known as the Allies, was a diplomatic alliance formed in 1907 between three major European powers: France, Russia, and Britain.

Based on this information, we can see that France, Russia, and Britain were all members of the Triple Entente, leaving Austria-Hungary as the nation state that was not part of this alliance.

Therefore, the correct answer is Austria-Hungary.