Answer – A and B
The AWS Documentation mentions the following.
Your Elastic Beanstalk includes an Auto Scaling group that manages the Amazon EC2 instances in your environment. In a single-instance environment, the Auto Scaling group ensures that there is always one instance running. In a load-balanced environment, you configure the group with a range of instances to run, and Amazon EC2 Auto Scaling adds or removes instances as needed, based on load.
The Auto Scaling group also manages the launch configuration for the instances in your environment. You can modify the launch configuration to change the instance type, key pair, Amazon Elastic Block Store (Amazon EBS) storage, and other settings that can only be configured when you launch an instance.
You can include a YAML formatted environment manifest in the root of your application source bundle to configure the environment name, solution stack and environment links to use when creating your environment. An environment manifest uses the same format as Saved Configurations.
Option C is invalid since this is used to ensure that the environment can interact with other AWS resources.
Option D is invalid since this is used to monitor the configuration changes of resources.
For more information on using the features of Elastic Beanstalk, please refer to the below URL-
https://docs.aws.amazon.com/elasticbeanstalk/latest/dg/using-features.managing.as.html