Exam AWS Certified Solutions Architect - Associate SAA-C03 topic 1 question 629 discussion

A blue/green deployment copies a production database environment to a separate, synchronized staging environment. You can make changes to the database in the staging environment without affecting the production environment. When you are ready, you can promote the staging environment to be the new production database environment, with downtime typically under one minute. https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/blue-green-deployments.html

You can make changes to the RDS DB instances in the green environment without affecting production workloads. For example, you can upgrade the major or minor DB engine version, upgrade the underlying file system configuration, or change database parameters in the staging environment. You can thoroughly test changes in the green environment. https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/blue-green-deployments-overview.html

Option A (Create an RDS manual snapshot and upgrade) is the most straightforward and least operationally intensive method to upgrade your Amazon RDS for MySQL instance while ensuring data safety and allowing thorough testing of application functionality post-upgrade. This approach leverages RDS's snapshot capabilities to provide a reliable rollback mechanism if needed, making it the recommended choice for your scenario.

Least overhead, only CD qualify and D is actually a managed solution for what is being proposed (hopefully) in C so it's better.

C works for me

D is the answer