You want several different subnets within your enterprise network to be reachable from outside the enterprise network. Your edge router must share a single route advertisement about these subnets with external devices. If one of the subnets is unavailable, your edge router should drop any traffic destined to that subnet. Which type of route, configured on the edge device with default behavior, accomplishes these objectives?

A.
an aggregate route

B.
a generated route

C.
a primary contributing route

D.
an OSPF route