A company plans to run a monitoring application on an Amazon EC2 instance in a VPC

Connections are made to the instance using its private IPv4 address. A solutions architect needs to design a solution that will allow traffic to be quickly directed to a standby instance if the application fails and becomes unreachable.

Which approach will meet these requirements?

1. Deploy an Application Load Balancer configured with a listener for the private IP address and register the primary instance with the load balancer. Upon failure, de-register the instance and register the secondary instance.
2. Configure a custom DHCP option set. Configure DHCP to assign the same private IP address to the secondary instance when the primary instance fails.
3. Attach a secondary elastic network interface (ENI) to the instance configured with the private IP address. Move the ENI to the standby instance if the primary instance becomes unreachable.
4. Associate an Elastic IP address with the network interface of the primary instance. Disassociate the Elastic IP from the primary instance upon failure and associate it with a secondary instance.