Your team is using AWS Elastic Beanstalk for web applications in a production environment. The project needs to read/write to a PostgreSQL RDS database in another production environment as well. Apart from this, the AWS Elastic Beanstalk also uses Immutable deployment and entirely new instances need to be created for new deployments. Among the options provided which one do you suggest to connect to RDS database for this Elastic Beanstalk environment?

Answer options:

A.For the Elastic Beanstalk, it is not possible to connect to a RDS instance if it is for production environment.
B.You could add this RDS database to Elastic Beanstalk using the database configuration card in the console. Type in the correct username, password, instance class and other information.
C.You could not add this RDS database to Elastic Beanstalk as Elastic Beanstalk does not support PostgreSQL.
D.Since it is for the production environment, it is suggested to put the RDS database outside of the AWS Elastic Beanstalk deployment. This can be done by using your web application to connect to it on launch.

Option D is Correct:
AWS Elastic Beanstalk provides support for running Amazon Relational Database Service (Amazon RDS) instances in your Elastic Beanstalk environment. This works great for development and testing environments. However, it isn`t ideal for a production environment because it ties the lifecycle of the database instance to the lifecycle of your application`s environment.
For more information, refer to
https://docs.aws.amazon.com/elasticbeanstalk/latest/dg/AWSHowTo.RDS.html
Option A is incorrect because it is still possible for the production environment.
Option B is incorrect: because this is a proper way if it is for development and test. However this question talks about the Elastic Beantalk environment for a production. For how to connect to the RDS in a Elastice Beanstalk environment, please refer to https://docs.aws.amazon.com/elasticbeanstalk/latest/dg/using-features.managing.db.html#using-features.managing.db.CON
Option C is incorrect: because you can use Elastic Beanstalk to add a MySQL, PostgreSQL, Oracle, or SQL Server database to your environment during or after environment creation. In this case, we should put the RDS instance outside of the Elastic Beanstalk environment.