A Startup Company Is Developing a Web Application on AWS

A startup company is developing a web application on AWS. It plans to use Amazon RDS for persistence and deploy the application to Amazon EC2 with an Auto Scaling group. The company would also like to separate the environments for development, testing, and production. What is the MOST secure approach to manage the application configuration?

A) Create a property file to include the configuration and the encrypted passwords. Check in the property file to the source repository, package the property file with the application, and deploy the application. Create an environment tag for the EC2 instances and tag the instances respectively. The application will extract the necessary property values based on the environment tag.
B) Create a property file for each environment to include the environment-specific configuration and an encrypted password. Check in the property files to the source repository. During deployment, use only the environment-specific property file with the application. The application will read the needed property values from the deployed property file.
C) Create a property file for each environment to include the environment-specific configuration. Create a private Amazon S3 bucket and save the property files in the bucket. Save the passwords in the bucket with AWS KMS encryption. During deployment, the application will read the needed property values from the environment-specific property file in the S3 bucket.
D) Create a property file for each environment to include the environment-specific configuration. Create a private Amazon S3 bucket and save the property files in the bucket. Save the encrypted passwords in the AWS Systems Manager Parameter Store. Create an environment tag for the EC2 instances and tag the instances respectively. The application will read the needed property values from the environment-specific property file in the S3 bucket and the parameter store.