How did the United States react to the Soviet Union’s development of an atomic bomb in 1949?

It initiated the Non-Proliferation Treaty.
It launched a full scale attack on the Soviet Union.
It initiated peaceful negotiations with the Soviet Union.
It began to develop a weapon more powerful than the atomic bomb.

Question

How did the United States react to the Soviet Union’s development of an atomic bomb in 1949?

It initiated the Non-Proliferation Treaty.
 It launched a full scale attack on the Soviet Union.
 It initiated peaceful negotiations with the Soviet Union.
 It began to develop a weapon more powerful than the atomic bomb.

Mercury · Answer

major hint: this was the event that started the Cold War "In particular, American officials encouraged the development of atomic weapons like the ones that had ended World War II. Thus began a deadly “arms race.” In 1949, the Soviets tested an atom bomb of their own. In response, President Truman announced that the United States would build an even more destructive atomic weapon: the hydrogen bomb, or “superbomb.”" https://www.history.com/topics/cold-war/cold-war-history