Conjugation in E

Conjugation in E. coli is controlled by an episome called the F factor. Cells containing F (F⁺ cells) are donors during gene transfer; cells lacking F (F^- cells) are recipients. Hfr cells possess F integrated into the bacterial chromosome; they donate DNA to F^- cells at a high frequency. F' cells contain a copy of F with some bacterial genes
-Conjugation between an F⁺ and an F^- cell usually results in

A) two F⁺ cells.
B) an F⁺ and an F^- cell.
C) an Hfr cell and an F⁺ cell