Figure 272 Depicts Changes to the Amount of DNA Present in in a Recipient

Figure 27.2 depicts changes to the amount of DNA present in a recipient cell that is engaged in conjugation with an Hfr cell. Hfr-cell DNA begins entering the recipient cell at Time A. Assume that reciprocal crossing-over occurs (i.e., a fragment of the recipient's chromosome is exchanged for a homologous fragment from the Hfr cell's DNA) . Use Figure 27.2 to answer the following questions.

Figure 27.2
-Which two processes are responsible for the shape of the curve at Time B?
1) transduction
2) entry of single-stranded Hfr DNA
3) rolling circle replication of single-stranded Hfr DNA
4) activation of DNA pumps in plasma membrane
5) "toilet paper" replication of recipient cell's plasmids

A) 1 and 4
B) 2 and 3
C) 3 and 5
D) 1 and 3
E) 4 and 5