How does Oppenheimer feel after the use of the first atomic
bomb?

After the war, Oppenheimer took steps to prevent such a future. He began working with the U.S. Atomic Energy Commission to control the use of nuclear weapons. In 1949, when Truman approached the commission about creating a hydrogen bomb, Oppenheimer opposed it.  But Oppenheimer's resistance ended up costing him his job

no statement

b or c ( this is because my answer is short so just ignore it)