The correct option is C J.M. Bishop and H.E. Varmus
An oncogene is a gene that has the potential to cause cancer. In tumor cells, oncogenes were first discovered in certain retroviruses and were identified as cancer-causing agents in many animals. In the mid 1970s, the American microbiologists, John Michael Bishop and Harold Varmus tested the theory that healthy body cells contain dormant viral oncogenes that, when triggered, cause cancer.
Thus, the correct answer is option (D), 'J.M. Bishop and H.E. Vermus'.