In Generalized Transduction, a Phage Introduces a Segment of Donor

In generalized transduction, a phage introduces a segment of donor DNA into the recipient cell. This is followed by recombination of the donor fragment with the recipient chromosome. Which of the following must occur?

A) circularization of the donor fragment before recombination
B) a pair (or even number) of crossovers between the donor segment and the recipient
C) degradation of one of the two strands of phage genome
D) replication of the donor segment before recombination
E) a single crossover between the donor segment and the recipient chromosome