Refer to the exhibit.

Which address range efficiently summarizes the routing table of the addresses for router Main?

A.
172.16.0.0./21

B.
172.16.0.0./20

C.
172.16.0.0./16

D.
172.16.0.0/18

Explanation:
The 172.16.0.0./20 network is the best option as it includes all networks from 172.16.0.0 –
172.16.16.0 and does it more efficiently than the /16 and /18 subnets. The /21 subnet will not
include all the other subnets in this one single summarized address.