The suggested answer is A, D.
In a public cloud environment, the cloud provider is responsible for maintaining the physical hardware and ensuring that it has sufficient capacity to meet user demands. Hardware maintenance involves actions like repair, replacement, and upgrades of physical servers, storage devices, and networking hardware. Hardware capacity management includes monitoring and managing the hardware resources to ensure there is always adequate capacity to meet the needs of all customers using the cloud services. The cloud provider's responsibility fundamentally covers these aspects to ensure the robustness and reliability of their infrastructure.