How Did the United States Respond to the Soviet Union's

How did the United States respond to the Soviet Union's testing of its first atomic bomb?

A) President Truman called for the formation of an international agency to control atomic energy.
B) Secretary of State Acheson asked that a summit be scheduled for negotiation of differences between the superpowers.
C) The United States called for an agreement between the superpowers on the number of nuclear-capable warheads each side would be allowed to have.
D) The United States began development of the hydrogen bomb.