A virtualized, multi-tenant architecture enabling tenants or users to share computing resources residing outside their firewalls best describes a characteristic for which cloud type?

The description provided aligns closely with the characteristics of a public cloud. In a public cloud environment, resources such as computing power, storage, and networking are made available over the internet to multiple tenants. Each tenant uses the same infrastructure and services while maintaining separate accounts and data. This model allows users to leverage the scalability and cost-effectiveness of shared resources that reside outside their own firewalls, which is a fundamental aspect of public cloud offerings.

Public clouds are commonly operated by third-party providers, allowing businesses and individuals to access powerful computing resources without the need to invest in their own physical hardware. This architecture supports a range of services and applications, making it suitable for various users and workloads.

In contrast, a private cloud is dedicated to a single organization and hosted either on-premises or in a dedicated environment, which means that its resources are not shared with other organizations. A hybrid cloud combines elements of both public and private clouds, offering greater flexibility but still primarily relies on the multi-tenant nature of public cloud services.

Hence, given the emphasis on sharing computing resources in a virtualized setting outside individual firewalls, the definition strongly supports public cloud as the correct answer.