The correct option is A DNAase
Oswald Avery, Colin MacLeod and Maclyn McCarty (1933-44) purified biochemicals (proteins, DNA, RNA, etc.) from the heat-killed S cells to see which ones could transform live R cells into S cells. They discovered that DNA from S bacteria caused R bacteria to become virulent. They also discovered that protein-digesting enzymes (Peptidase) and RNA-digesting enzymes (RNases) did not affect transformation, so the transforming substance was not a protein or RNA. Digestion with DNase did inhibit transformation, suggesting that the DNA caused the transformation. Thus they concluded that DNA is the hereditary material,