Answer: Amazon EC2 operating system patching, API access control for AWS resources

## Explanation Under the AWS Shared Responsibility Model: - **Amazon EC2 operating system patching (B)** - This is the customer's responsibility. AWS manages the underlying infrastructure, but customers are responsible for patching the operating systems and applications running on their EC2 instances. - **API access control for AWS resources (C)** - This is the customer's responsibility. Customers must manage IAM policies, user access, and API permissions for their AWS resources. ### Why other options are NOT customer responsibilities: - **Hardware maintenance (A)** - AWS responsibility - **Configuration management of infrastructure devices (D)** - AWS responsibility (AWS manages the physical infrastructure) - **Maintenance of an Availability Zone (E)** - AWS responsibility In the shared responsibility model, AWS is responsible for security **OF** the cloud (infrastructure), while customers are responsible for security **IN** the cloud (their data, applications, operating systems, etc.).

Author: Ritesh Yadav