For which customers is this recommendation valid?

The account manager at YourDomain .com recommends a WAN solution with universal gateways.
For which customers is this recommendation valid?

A.
For customers that requires flexibility for remote workers who connect to the company from their homes.

B.
For customers that have enterprise branch offices that must connect to the Internet over the Public Switched Telephone Network (PSTN).

C.
For customers that requires collaboration between project teams at different locations around campus.

D.
For customers that requires mobility for offsite personnel who work at local client locations.