I might not be quite right with that one

In which of these cases would you be most likely to use a cable with a DB-9 connector?

A) Connecting an external storage device

B) Attaching a mouse or keyboard to a desktop computer

C) Configuring a router

D) Connecting a POTS line to a modem

E) Attaching a video camera to a computer

F) When a DB-8 cable is too short