Explanation

Correct Answer: A

Why Option A is correct:

1. Instance Scheduler on AWS is specifically designed for automating the start and stop schedules of AWS resources including Amazon RDS instances.
2. It can be configured to automatically start the RDS instance on weekdays before business hours and stop it after business hours, weekends, and holidays.
3. This directly reduces costs by only running the database when needed, while minimizing operational overhead through automation.
4. The Instance Scheduler is a managed AWS solution that requires minimal setup and maintenance.

Why Option B is incorrect:

1. Turning off automatic backups and creating manual snapshots reduces backup costs but doesn't address the main requirement of stopping the database during non-business hours.
2. The RDS instance would still be running 24/7, incurring unnecessary costs.
3. Manual snapshots increase operational overhead rather than reducing it.

Why Option C is incorrect:

1. While a custom Lambda function could technically achieve the same result, it increases operational overhead rather than reducing it.
2. The company would need to develop, test, deploy, and maintain the custom solution.
3. The Instance Scheduler is a pre-built, managed solution that's more reliable and requires less operational effort.

Why Option D is incorrect:

1. Purchasing All Upfront reserved DB instances provides cost savings but doesn't address the requirement to stop the database during non-business hours.
2. Reserved instances are designed for steady-state workloads that run continuously, not for intermittent usage patterns.
3. The database would still run 24/7, wasting resources during off-hours.

Key AWS Services:

• Instance Scheduler on AWS: A solution that automates the starting and stopping of Amazon EC2 and Amazon RDS instances.
• Amazon RDS: Relational Database Service that supports automated backups, snapshots, and scheduled operations.

Best Practice: For workloads with predictable usage patterns (like business hours only), using the Instance Scheduler is the most cost-effective and operationally efficient approach.