Suppose that two strains of E. coli - strain a (bio- met- leu+ thr+ thi+) and strain b (bio+ met+ leu- thr- thi-) - conjugate. If the two strains are grown on minimal medium, what is the most likely genotype of their offspring?
A) bio+ met- leu- thr- thi+ B) bio+ met+ leu+ thr+ thi+ C) bio+ met+ leu- thr- thi+ D) bio- met- leu- thr- thi+