What Is Known as the "Long Peace

What is known as the "Long Peace"?

A) The special relationship and alliance between the United States and Great Britain.
B) The relative infrequency of war between states in South America.
C) The fact that there has never been a nuclear war.
D) The absence of war between the United States,Mexico,and Canada since 1848.
E) The absence of war between the United States and the Soviet Union during the Cold War.