Explanation

Under the AWS Shared Responsibility Model:

AWS is responsible for "Security OF the Cloud":

• Physical infrastructure (data centers, hardware, networking)
• Infrastructure devices configuration
• Virtualization layer
• Global infrastructure security

Customer is responsible for "Security IN the Cloud":

• Managing and encrypting application data (Option A)
• Installing OS updates and security patches (Option B)
• Configuring security groups (Option D)
• Application security and identity management

Why Option C is correct:

• Configuration of infrastructure devices (servers, switches, routers, networking hardware) falls under AWS's responsibility
• AWS manages the underlying infrastructure that powers EC2 instances
• This includes physical security, hardware maintenance, and network infrastructure configuration

Why other options are incorrect:

• Option A: Application data management and encryption is customer responsibility
• Option B: Guest OS patching is customer responsibility
• Option D: Security group configuration is customer responsibility

This is a common exam question that tests understanding of the shared responsibility model boundaries.