Which dial plan scenario may require PSTN trunks for ountbound?

A.
All employees,autoattendant or receptionist and voicemail and the remaining employess do not have direct inward dial numbers

B.
All employees,autoattendant or receptionist and voicemail have direct inwaqrd dial numbers using analog trunks

C.
All employees,autoattendant or receptionist and voicemail have direct inwaqrd dial numbers using digital interfaces