Which of the below mentioned options is a possible reason for rejection?

A user is trying to connect to a running EC2 instance using SSH. However, the user gets a Host
key not found error. Which of the below mentioned options is a possible reason for rejection?

A.
The user has provided the wrong user name for the OS login

B.
The instance CPU is heavily loaded

C.
The security group is not configured properly

D.
The access key to connect to the instance is wrong

Explanation:
If the user is trying to connect to a Linux EC2 instance and receives the Host Key not found error
the probable reasons are:
The private key pair is not right
The user name to login is wrong