Explanation

Correct Answer: C - Configure each development environment with its own Amazon Aurora On-Demand PostgreSQL-Compatible database

Why Option C is the most cost-effective:

1. Aurora On-Demand vs. Aurora Standard: Aurora On-Demand databases are designed for intermittent workloads where you only pay for compute capacity when the database is active. Since each development environment is used for only half of the 8-hour workday (approximately 4 hours per day), On-Demand pricing would be significantly cheaper than running a database 24/7.

2. Development Environment Characteristics:

   • Development environments are typically used intermittently
   • They don't need to be running 24/7
   • Developers can start/stop databases as needed
   • Data persistence is less critical than in production

3. Comparison with other options:

   • Option A (Aurora PostgreSQL database): This would run 24/7, incurring costs even when not in use
   • Option B (RDS Single-AZ): Also runs 24/7, and RDS is generally more expensive than Aurora for equivalent performance
   • Option D (S3 buckets): S3 is not a relational database solution and cannot run PostgreSQL schemas

4. Cost Optimization Strategy:

   • Aurora On-Demand allows you to pay only for the compute capacity when the database is active
   • When developers are not working (nights, weekends, lunch breaks), the database can be stopped, incurring no compute charges
   • Storage costs would still apply, but these are minimal compared to compute costs

Key AWS Cost Optimization Principles Applied:

• Right-sizing: Using On-Demand instead of 24/7 instances
• Stop idle resources: Development databases don't need to run continuously
• Choose appropriate service: Aurora On-Demand is specifically designed for intermittent workloads

This solution provides the required PostgreSQL compatibility while minimizing costs by only paying for compute when developers are actively using their environments.