A User Has Created a VPC with CIDR 20

Multiple Choice

A user has created a VPC with CIDR 20.0.0.0/16. The user has created one subnet with CIDR 20.0.0.0/16 in this VPC. The user is trying to create another subnet with the same VPC for CIDR 20.0.0.1/24. What will happen in this scenario?

A) The VPC will modify the first subnet CIDR automatically to allow the second subnet IP range
B) It is not possible to create a subnet with the same CIDR as VPC
C) The second subnet will be created
D) It will throw a CIDR overlaps error