A User Has Created a VPC with CIDR 20

Multiple Choice

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