A User Has Launched Five Instances and Have Registered Them

Multiple Choice

A user has launched five instances and have registered them with an ELB. How can the user add the sixth EC2 instance to the ELB?

A) The user must stop the ELB and add the sixth instance.
B) The user can add the sixth instance on the fly through API, CLI or the AWS Management Con-sole.
C) The user can add the instance and change the ELB config file.
D) The ELB can only have a maximum of five instances.