A user has created a VPC with CIDR 20.0.0.0/24. The user has created a public subnet with CIDR
20.0.0.0/25. The user is trying to create the private subnet with CIDR 20.0.0.128/25. Which of the
below mentioned statements is true in this scenario?

A.
It will not allow the user to create the private subnet due to a CIDR overlap

B.
It will allow the user to create a private subnet with CIDR as 20.0.0.128/25

C.
This statement is wrong as AWS does not allow CIDR 20.0.0.0/25

D.
It will not allow the user to create a private subnet due to a wrong CIDR range

Explanation:
When the user creates a subnet in VPC, he specifies the CIDR block for the subnet. The CIDR
block of a subnet can be the same as the CIDR block for the VPC (for a single subnet in the VPC.,
or a subset (to enable multiple subnets.. If the user creates more than one subnet in a VPC, the
CIDR blocks of the subnets must not overlap. Thus, in this case the user has created a VPC with
the CIDR block 20.0.0.0/24, which supports 256 IP addresses (20.0.0.0 to 20.0.0.255.. The user
can break this CIDR block into two subnets, each supporting 128 IP addresses. One subnet uses
the CIDR block 20.0.0.0/25 (for addresses 20.0.0.0 – 20.0.0.127. and the other uses the CIDR
block 20.0.0.128/25 (for addresses 20.0.0.128 – 20.0.0.255..