A company runs an RDS for PostgreSQL database continuously. Its instance class, Region, and deployment configuration are expected to remain stable for three years. The company wants a discount on eligible database instance usage without changing the database engine. Which option is the best match?

1. Spot purchasing for the existing RDS DB instance.
2. A matching RDS Reserved DB instance offering, after verifying configuration and term applicability.
3. A Compute Savings Plan purchased specifically to cover RDS instance charges.
4. Stop the production database every evening even though the application requires continuous availability.