In the classic experiment conducted by Hershey and Chase, why was the pellet radioactive in the ...

In the classic experiment conducted by Hershey and Chase, why was the pellet radioactive in the centrifuge tube that contained bacteria with viruses?
 
  A) The radioactive viruses (coats plus DNA) were in the pellet.
  B) The radioactive protein coats of the viruses were in the pellet.
  C) The bacteria were in the pellet, and they had incorporated radioactive proteins into their cell membranes.
  D) The radioactive viruses were in the pellet, and the bacteria were in the supernatant.
  E) The bacteria were in the pellet, and many contained the radioactive viral DNA.