Which of the following enables CSPs to offer unlimited capacity to customers?

Adequate budget is a prerequisite for building infrastructure but does not by itself create the operational model or cost structure that enables unlimited on-demand capacity for customers.

Global data center distribution improves availability, fault tolerance, and latency but does not directly explain how unlimited capacity is economically feasible - it describes geography, not scale economics.

Cloud service providers aggregate compute, storage, and network demand across millions of customers, which justifies enormous capital investment in data centers that individual organizations could never fund alone. This aggregation lowers the marginal cost of each additional unit of capacity, allowing CSPs to absorb demand spikes and present a virtually unlimited resource pool to any single customer. The cost savings from operating at hyperscale are the economic foundation of the cloud's elastic capacity model.

Agile project management is a software development methodology for iterative delivery and has no direct relationship to the physical or economic capacity of a cloud provider's infrastructure.