Final answer:
Strains A and C have similar gene transfer sequences indicating that their F factors are cooriented. The gene order in strain B does not show a similar overlap with either A or C, which suggests it is not cooriented with them.
Step-by-step explanation:
The orientation of the F factors in each of the three Hfr strains (A, B, and C) can be deduced by analyzing the order in which genes are transferred during interrupted-mating experiments. By comparing the sequence of genes transferred from each strain, it becomes clear which Hfr strains have cooriented F factors.
For strain A, the gene transfer order is thi-his-gal-lac-pro, for strain B it's azi-leu-thr-thi-his, and for strain C the order is lac-gal-his-thi-thr. By identifying matching sequences and their directions, we can determine the orientation. In this case, strains A and C both have the thi and his genes in the same order, indicating a similar orientation. Additionally, the presence of lac and gal genes early in the transfer sequence for strain C reveals that it begins transferring genes from a point close to that of strain A.
Thus, the F factors in strains A and C are cooriented, and their gene transfer sequences overlap significantly, although they start at different points in the chromosome. There is no such direct sequence and direction match between strains B and either A or C, hence B is not cooriented with A or C. Therefore, the correct answer is c. A and C are cooriented.