CISCO CCNA Exam – Q138

Refer to the exhibit.
CISCO CCNA Exam – Q138

In this VLSM addressing scheme, what summary address would be sent from router A?

A. /16
B. /20
C. /24
D. /16
E. /17
F. /16

Correct Answer: A

Router A receives 3 subnets:, and
All these 3 subnets have the same form of 172.16.x.x so our summarized subnet must be also in that form.
The smallest subnet mask of these 3 subnets is /18 so our summarized subnet must also have its subnet mask equal or smaller than /18.
Only answer A has these 2 conditions .