Which type of cloud is represented by a local Internet service provider upgrading its infrastructure to provide cloud services to all subscribers?

The correct choice is public cloud. A public cloud is characterized by services offered over the Internet and made available to the general public or a large industry group. In this scenario, when a local Internet service provider upgrades its infrastructure to provide cloud services, it is likely doing so to serve multiple subscribers without restricting access to specific organizations or individuals. This aligns with the definition of a public cloud, where resources and services are shared among numerous users, leveraging a centralized infrastructure managed by the service provider.

In contrast, a private cloud would involve exclusive resources and services allocated for a single entity. A community cloud would be tailored for a specific community of users with shared concerns, possibly related to security or compliance. Hybrid cloud refers to a combination of on-premises and cloud resources, enabling data and applications to be shared between them. Each of these alternatives points to different cloud utilization models that do not fit the scenario presented.