In Hershey Chase experiment, protein tagging was done by
Radioactive Phosphorus 37P
Radioactive Sulphur 35S
Radioactive Phosphorus 35P
Radioactive Sulphur 37S
As we have already studied in Hershey & Chase Experiment -
The viruses are grown in the medium containing radioactive sulfur (35S) now contained radioactive protein (not radioactive DNA). This is because DNA does not contain sulfur.
Hence, the correct option is (b).