How did Avery design the experiment that allowed him to form the conclusion that DNA is the transforming factor?

A. Avery isolated DNA,RNA and proteins from the live S strain and mixed them individually with the live R strain
B. Avery isolated DNA,RNA and proteins from the live R strain and mixed them individually with the killed S strain
C. Avery isolated DNA,RNA and proteins from the killed S strain and mixed them individually with the live R strain
D. Avery isolated DNA,RNA and proteins from the killed R strain and mixed them individually with the live S strain