Read the following passage carefully and answer the questions following it. Certain words have been highlighted for your attention.

Cloud computing is the use of data centre servers and software networks to dynamically allocate resources and run applications for remote end users. Typically divided into three categories (private, public, and hybrid) cloud deployments have grown rapidly in recent years, promising cost savings and greater flexibility over traditional private data centres. 

Virtualisation is key for cloud computing. By allowing physical servers to run one or more virtual machines on demand, cloud architectures offer rapid scaling and efficient allocation of server resources on the fly. Private cloud refers to cloud infrastructure dedicated to a single company and accessed by a private network connection, operating on servers managed either internally or by a third-party provider. For many organisations in highly regulated industries, private clouds remain the solution of choice. Cloud infrastructure platforms such as OpenStack offer a framework for private cloud deployment and management, and a bevy of vendors have begun releasing supported versions of the open source platform.

The public cloud ___________ (A) Amazon Web Services, which sell server resources (rather than dedicated physical servers) accessed over a public network such as the Internet. Hybrid cloud (sometimes called 'cloud bursting') is the combination of multiple clouds. For example, a company could use public cloud services to handle temporary bursts of activity that exceed private cloud capacity. Some companies also use private clouds for certain sensitive business units while hosting less critical applications on the public cloud.