When two terminals are making a point-to-point number call, when will the called single-selection terminal send a call request to GK?

When two terminals are making a point-to-point number call, when will the called single-selection terminal send a call request to GK?
A . After the called party sends the connect message A
B . After receiving the setup signaling, the called party
C . After the called party sends call proceeding
D . After the called party conducts master-slave negotiation with the calling party

Answer: B