What does the ec2-revoke command do with respect to the Amazon EC2 security groups?
A.
Removes one or more security groups from a rule.
B.
Removes one or more security groups from an Amazon EC2 instance.
C.
Removes one or more rules from a security group.
D.
Removes a security group from an account.
http://docs.aws.amazon.com/cli/latest/reference/ec2/revoke-security-group-ingress.html
Removes one or more ingress rules from a security group. The values that you specify in the revoke request (for example, ports) must match the existing rule’s values for the rule to be removed.
To remove a rule from a security group
This example removes TCP port 22 access for the 203.0.113.0/24 address range from the security group named MySecurityGroup. If the command succeeds, no output is returned.
aws ec2 revoke-security-group-ingress –group-name MySecurityGroup –protocol tcp –port 22 –cidr 203.0.113.0/24