On which medium were the viruses cultivated by Alfred Hershey and Martha Chase?

Q. On which medium were the viruses cultivated by Alfred Hershey and Martha Chase?

A.            A medium containing radioactive potassium (K)

B.            A medium containing radioactive Uranium (U)

C.            A medium containing radioactive phosphorous (P)

D.            A medium containing potassium (K)

Answer: A medium containing radioactive phosphorous (P)