Which responsibility belongs to AWS when a company hosts its databases on Amazon EC2 instances?

Explanations:

While AWS provides infrastructure services, the responsibility for database backups falls on the customer. They must implement their own backup solutions or use AWS services like RDS or S3 for this purpose.

Database software patches are the responsibility of the customer. When hosting databases on EC2, users must manage the patching and maintenance of the database software themselves.

Operating system patches are also the responsibility of the customer. Users need to manage OS updates and security patches for the EC2 instances where their databases are hosted.

Operating system installations are the responsibility of AWS in terms of providing the infrastructure, but the actual installation of the operating system and its configuration are managed by the customer on EC2 instances. AWS provides the images, but users are responsible for the setup and maintenance.