Bacteriophage Lambda Maintains the Lysogenic Phase of Its Life Cycle

Bacteriophage lambda maintains the lysogenic phase of its life cycle when

A) high levels of cI and high levels of cro proteins are present in bacterial cells
B) low levels of cI and high levels of cro proteins are present in bacterial cells
C) high levels of cI and low levels of cro proteins are present in bacterial cells
D) low levels of cI and low levels of cro proteins are present in bacterial cells
E) none of these conditions maintains lysogeny