You have a subnet with a CIDR block of 10.0.1.0/24. Which of the following is not an IP address which would be assigned to an EC2 Instance launched in this subnet

Answer options:

A.10.0.1.4
B.10.0.1.253
C.10.0.1.3
D.10.0.1.254

Answer – C
The AWS Documentation mentions the following
The first four IP addresses and the last IP address in each subnet CIDR block are not available for you to use, and cannot be assigned to an instance. For example, in a subnet with CIDR block 10.0.0.0/24, the following five IP addresses are reserved:
· 10.0.0.0: Network address.
· 10.0.0.1: Reserved by AWS for the VPC router.
· 10.0.0.2: Reserved by AWS. The IP address of the DNS server is always the base of the VPC network range plus two; however, we also reserve the base of each subnet range plus two. For VPCs with multiple CIDR blocks, the IP address of the DNS server is located in the primary CIDR. For more information, see Amazon DNS Server.
· 10.0.0.3: Reserved by AWS for future use.
· 10.0.0.255: Network broadcast address. We do not support broadcast in a VPC, therefore we reserve this address.
 For more information on subnets and VPC’s, please refer to below URL:
http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/VPC_Subnets.html#vpc-subnet-basics