Which statements about best practice is MOST correct?

Customers define requirements and provide feedback on outcomes, but they are not authoritative sources of best practice for how service providers should structure or run their processes.

Internal experience is limited to a single organization's situations and cannot be validated across diverse environments, making it insufficient as the sole source of best practice.

ITIL is a publicly available framework continuously refined through input from practitioners across many industries and organizational types, giving it broad cross-environment validation. Unlike internal experience or stakeholder-specific input, ITIL synthesizes lessons from a wide range of service providers, making it the recognized authoritative source of IT service management best practice.

Suppliers are responsible for delivering agreed services or components, not for defining validated best practice frameworks applicable across the wider service management industry.