73. A partial diploid E. coli with which of the following genotypes would turn blue on the plate containing X-Gal in the
presence or absence of the inducer IPTG? (A) I+
O+
lacZ+
/ I+
O+
lacZ-
(B) IO+
lacZ+
/ I+
O+
lacZ-
(C) I+
Oc
lacZ-
/ I+
O+
lacZ+
(D) I+
Oc
lacZ+
/ I+
O+
lacZ+
(E) I+
Oc
lacZ-
/ IO+
lacZ+