User A and user B belong to different city servers, and both parties have only one landline at home that can be used for calls. If user A calls user B when user B calls out, the number of transactions included in the entire session is?

User A and user B belong to different city servers, and both parties have only one landline at home that can be used for calls. If user A calls user B when user B calls out, the number of transactions included in the entire session is?
A . 4
B.3
C.5
D.6

View Answer

Answer: A