Which subnet mask should you use for the Pod IP address range?

You need to define an address plan for a future new Google Kubernetes Engine (GKE) cluster in your Virtual Private Cloud (VPC). This will be a VPC-native cluster, and the default Pod IP range allocation will be used. You must pre-provision all the needed VPC subnets and their respective IP address ranges before cluster creation. The cluster will initially have a single node, but it will be scaled to a maximum of three nodes if necessary. You want to allocate the minimum number of Pod IP addresses.

Which subnet mask should you use for the Pod IP address range?
A . /21
B. /22
C. /23
D. /25

Answer: A