A Company Has a Two-Tier Application Architecture That Runs in Public

A company has a two-tier application architecture that runs in public and private subnets. Amazon EC2 instances running the web application are in the public subnet and a database runs on the private subnet. The web application instances and the database are running in a single Availability Zone (AZ) . Which combination of steps should a solutions architect take to provide high availability for this architecture? (Choose two.)

A) Create new public and private subnets in the same AZ for high availability.
B) Create an Amazon EC2 Auto Scaling group and Application Load Balancer spanning multiple AZs.
C) Add the existing web application instances to an Auto Scaling group behind an Application Load Balancer.
D) Create new public and private subnets in a new AZ. Create a database using Amazon EC2 in one AZ.
E) Create new public and private subnets in the same VPC, each in a new AZ. Migrate the database to an Amazon RDS multi-AZ deployment.