Vlsm

ISP has given IP address 172.16.1.128/24 where there are several subnetworks has to be created by the administrator in order to connect several branch offices along with Head Quarters.
The organisation requirement are as folows:
Network no. of host
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Network A - 14 (Total)
Network B - 18 (Valid)
Network C - 20
Network D - 29

Network E - 2
Network F - 2
Network G - 2
Network H - 2
Network I - 2
Network J - 2
Network K - 2
Network L - 2

Network E,F,G,H,I,J,K,L are serial to serial.
Claculate