What is the primary difference between cloud computing and a data center?

The primary difference highlighted in the chosen answer centers around the nature of cloud computing as a service. Cloud computing solutions are inherently designed to provide scalable resources and services over the internet or a network, allowing users to access and utilize computing power, applications, and storage on demand. This model contrasts with traditional data centers, which typically require significant upfront investment in physical hardware and infrastructure to maintain.

In cloud computing, resources can be provisioned as needed and users can leverage vast pools of resources maintained by cloud service providers. This on-demand model facilitates flexibility, scalability, and accessibility from various devices and locations. Users can tap into these services without having to manage the underlying physical hardware, which is a key advantage that cloud computing offers over traditional data centers.

The other choices, while they address aspects related to security, physical infrastructure, and access methods, do not capture the essential distinction of service delivery and resource utilization integral to cloud computing. Cloud solutions represent a shift from hardware ownership to service-based access facilitated through the network, making option B the most accurate in conveying the primary difference.