Choose the sentence from this excerpt that best supports the claim that Klaus Fuchs should not have been allowed to work on the Manhattan Project.
1. Japan was an enemy during World War II; it had continued to fight after its ally, Germany, had surrendered in May.
2. The United States dropped a second bomb three days later, on August 9.
3. After the war, Fuchs returned to England.
4. The evidence specifically involved the passing of atomic bomb secrets.