In the Experiments of Griffith, the Conversion of Nonlethal R-Strain

In the experiments of Griffith, the conversion of nonlethal R-strain bacteria to lethal S-strain bacteria:

A) was the result of genetic mutation.
B) was an example of the genetic exchange known as transformation.
C) supported the case for proteins as the genetic material.
D) could not be reproduced by other researchers.
E) was an example of conjugation.