Refer to the exhibit.
What is the most efficient summarization that R1 can use to advertise its networks to R2?
A. 172.1.4.0/25
172.1.4.128/25
172.1.5.0/24
172.1.6.0/24
172.1.7.0/24
B. 172.1.0.0/22
C. 172.1.4.0/24
172.1.5.0/24
172.1.6.0/24
172.1.7.0/24
D. 172.1.0.0/21
E. 172.1.4.0/22
