Which of the Following Strains Will Be Useful in Demonstrating

Multiple Choice

Which of the following strains will be useful in demonstrating cis- regulation? In the genotypes listed below,the genes on the chromosome are on the left of the slash (/) symbol and the genes F' episome are on the right.

A) lacI⁺ lacO⁺ lacZ⁺/lacI⁺ lacO⁺ lacZ⁺
B) lacI⁺ lacO^c lacZ⁺/lacI⁺ lacO⁺ lacZ^-
C) lacI⁺ lacO⁺ lacZ⁺/lacI⁺ lacO^c lacZ^-
D) lacI⁺ lacO⁺ lacZ⁺/lacI^s lacO⁺ lacZ^-
E) lacI^s lacO⁺ lacZ⁺/lacI⁺ lacO⁺ lacZ^-