The CCSK v5.0 Study Guide defines cloud computing based on the NIST SP 800-145 definition, which outlines five essential characteristics: on-demand self-service, broad network access, resource pooling, rapid elasticity, and measured service. Two key capabilities that underpin these characteristics areabstractionandresource pooling.

Abstractionrefers to the virtualization layer that hides the underlying physical infrastructure, allowing users to interact with resources (e.g., compute, storage, networking) without needing to manage the hardware directly.

Resource poolingenables the provider’s computing resources to be pooled to serve multiple consumers using a multi-tenant model, with resources dynamically assigned and reassigned based on demand.

From theCCSK v5.0 Study Guide, Domain 1 (Cloud Computing Concepts and Architectures), Section 1.2:

“Cloud computing relies on abstraction to simplify the user experience and resource pooling to efficiently allocate resources across multiple tenants. Resource pooling is a defining characteristic, where the provider’s computing resources are pooled to serve multiple consumers, with different physical and virtual resources dynamically assigned and reassigned according to consumer demand.”

Option B correctly identifiesabstraction and resource poolingas the two key capabilities.

Option A (Abstraction and orchestration) is incorrect because orchestration, while important for automation, is not a defining characteristic of cloud computing.

Option C (Multi-tenancy and isolation) is incorrect because, while multi-tenancy is a feature of resource pooling, isolation is a security mechanism, not a core capability of cloud computing.

Option D (Virtualization and multi-tenancy) is incorrect because virtualization is a technology that enables abstraction, but multi-tenancy alone is not sufficient to define cloud computing.