You Mix Met⁺ Pro⁻ Lys⁺,and Met⁻ Pro⁺ Lys⁺ Auxotrophic Strains

You mix Met⁺ Pro⁻ Lys⁺,and Met⁻ Pro⁺ Lys⁺ auxotrophic strains of E.coli.After incubation time has passed,you place 10¹⁰ cells per plate on agar to detect potential prototrophic colonies.How many plates need to be screened if gene transfer takes place only through random mutation?

A) approximately 10
B) approximately 1000
C) approximately 100,000
D) none is a correct estimate
E) only one plate would be necessary