The correct answer is “because he had friends and family that belonged to the Communist Party.”
In 1954, after he had helped develop the atomic bomb, J. Robert Oppenheimer was investigated and denied future access to classified information because he had friends and family that belonged to the Communist Party.
Robert Oppenheimer (1904-1967) was a physicist that participated in the Manhattan Project that developed the atomic bomb. He was the Director of the Los Alamos laboratory, where he researched and designed the bomb. He is considered the father of the atomic bomb.
During the Second Red Scare of 1954, his security clearance was revoked, The scientific community supported Oppenheimer. So it is correct to say that in 1954 after he had helped develop the atomic bomb, J. Robert Oppenheimer was investigated and denied future access to classified information because he had friends and family that belonged to the Communist Party.