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.