A company requires that its internally facing web application be highly available. The architecture is made up of one Amazon EC2 web server instance and one NAT instance that provides outbound internet access for updates and accessing public data.
Which combination of architecture adjustments should the company implement to achieve high availability? (Choose two.)

A. Add the NAT instance to an EC2 Auto Scaling group that spans multiple Availability Zones. Update the route tables.
B. Create additional EC2 instances spanning multiple Availability Zones. Add an Application Load Balancer to split the load between them.
C. Configure an Application Load Balancer in front of the EC2 instance. Configure Amazon CloudWatch alarms to recover the EC2 instance upon host failure.
D. Replace the NAT instance with a NAT gateway in each Availability Zone. Update the route tables.
E. Replace the NAT instances with a NAT gateway that spans multiple Availability Zones. Update the route tables.