Successful cotransformation in the yeast two-hybrid system will result in the binding of proteins produced by each yeast expression vector.These fusion proteins function by

A)binding to the lacZ operator,preventing transcription.
B)binding to RNA polymerase,preventing transcription.
C)binding to the lacZ repressor,enabling transcription.
D)binding to the lacZ upstream activator sequence,enabling transcription.
E)changing color in the presence of X-gal.