Oswald Avery Expanded on Griffith's Experiment to Prove the "Factor

Oswald Avery expanded on Griffith's experiment to prove the "factor" carried by the bacteria was DNA instead of protein. What change did Avery implement when he modified Griffith's experiment?

A) Avery radioactively labeled the DNA in the bacteria. This allowed Avery to track the genetic material and prove the DNA was directly responsible for killing the mouse.
B) Avery used an enzyme that broke down the DNA molecule which resulted in a live mouse in the last step of the experiment. Because the DNA was inactivated, the bacteria was not transformed to make the capsule around it.
C) Avery radioactively labeled the amino acids and was able to track the production of the protein by the bacteria. This concluded the protein came from the DNA.
D) Avery used an enzyme that broke down the capsule proteins. Even though the proteins were inactivated, the mouse still died. This proved the "factor" was not a protein.