After Griffiths 1928 experiments leading to the discovery of the Transforming Principle,subsequent experimentation demonstrated that:

A) The transforming principle could not be carried out in vitro
B) The conversion of Type IIIR to Type IIIS was due to mutation
C) The process of heat-killing cells was not entirely effective.
D) DNAse treatment eliminates all transforming activity
E) RNAse treatment eliminates all transforming activity