A Customer Is Running a Critical Payroll System in a Production

A customer is running a critical payroll system in a production environment in one data center and a disaster recovery (DR) environment in another. The application includes load-balanced web servers and failover for the MySQL database. The customer's DR process is manual and error-phone. For this reason, management has asked IT to migrate the application to AWS and make it highly available so that IT no longer has to manually fail over the environment. How should a Solutions Architect migrate the system to AWS?

A) Migrate the production and DR environments to different Availability Zones within the same region. Let AWS manage failover between the environments.
B) Migrate the production and DR environments to different regions. Let AWS manage failover between the environments.
C) Migrate the production environment to a single Availability Zone, and set up instance recovery for Amazon EC2. Decommission the DR environment because it is no longer needed.
D) Migrate the production environment to span multiple Availability Zones, using Elastic Load Balancing and Multi-AZ Amazon RDS. Decommission the DR environment because it is no longer needed.