A.If a switch is used, the collision domain includes all devices connected to the switch.
B.If a hub is used, the collision domain includes all devices connected to the hub.
C.If a hub is used, the collision domain is limited to each device and the hub.
D.If a switch is used, the collision domain is limited to each device and the switch.

A.Routers facilitate communications within a broadcast domain.
B.Routers facilitate communications between broadcast domains.
C.Routers are used to break up broadcast domains into separate networks.
D.Routers are used to connect small broadcast domains and form larger more efficient broadcast domains