Which route summarization most efficiently reduces perceived network complexity that is composed of subnetworks ranging from 172.16.20.0/24 to 172.16.36.0/24?
A. 172.16.8.0/21
B. 172.16.8.0/19
C. 172.16.20.0/20
D. 172.16.0.0/18
E. 172.16.20.0/19