Multiple containers can run on the same virtual machine or be implemented without the use of VMs at all and run directly on hardware. The container provides code running inside a restricted environment with only access to the processes and capabilities defined in the container configuration. This allows containers to launch incredibly rapidly. since they don't need to boot an operating system or launch many(sometimes any) new services; the container only needs access to already-running services in the host 0S and some can launch in milliseconds.
Reference: CSA Security Guidelines V.4(reproduced here for the educational purpose)

It is important to read the question carefully and then choose the best answer. Although cloud consumer is responsible for authorizations and entitlements across all service models but questions uses
"only''. Therefore, answer is Software as a Service (SaaS) and a SaaS provider is responsible for perimeter security, logging/ monitoring/auditing, and application security.

It is the characteristic of 0n-demand self-service that allows customers to scale their computer and/ or storage needs with little or no intervention from or prior communication with the provider