According to the AWS shared responsibility model, customers are responsible for managing their data, applications, operating systems, security groups, and other aspects of their AWS environment. This includes installing updates and security patches of the guest operating system and any application software or utilities installed by the customer on the instances. AWS is responsible for protecting the infrastructure that runs all of the services offered in the AWS Cloud, such as data centers, hardware, software, networking, and facilities. This includes the physical connectivity among Availability Zones, the network switch maintenance, and the hardware updates and firmware patches. Therefore, option D is the correct answer, and options A, B, and C are AWS responsibilities, not customer responsibilities. References: : AWS Well-Architected Framework - Elasticity; : Reactive Systems on AWS - Elastic