Griffith's experiments along with Avery, MacLeod and McCarty helped to determine the transforming factors of Pneumococcus bacteria. Using heat-killed S-strain bacteria and one particular fraction of the cell lysates, they were able to demonstrate that _____ and not ______ was responsible for the basis of lethality of the strain.

a. proteins, DNA
b. DNA, proteins
c. deoxyribonuclease, mucous coat
d. polysaccharides, proteins

I assume the answer is "b" because DNA indeed is resposible for the basis of lethality of the strain. am I right?

Yes, you are correct. The answer is option b: DNA, proteins. Griffith's experiments, along with Avery, MacLeod, and McCarty, demonstrated that DNA, not proteins, was responsible for the transforming factor of Pneumococcus bacteria. They used heat-killed S-strain bacteria and extracted a particular fraction of the cell lysates, which contained DNA. By introducing this fraction into live R-strain bacteria, they observed that the R-strain bacteria were transformed into the lethal S-strain, indicating that DNA was the genetic material responsible for the characteristics of the S-strain bacteria.