In ITIL 4, “service consumer” is a generic term that includes three specific roles:

Customer – the person or group that defines the requirements for a service and takes responsibility for the outcomes of service consumption.

User – the person or group that actually uses the service.

Sponsor – the person or group that authorizes the budget for service consumption.

So, specifically:

The customer is responsible for defining the requirements for the service and for the overall outcomes expected from the service.

The sponsor is the one who authorizes the budget (not the customer, unless they are playing both roles in a given context).

The user is the one who uses the service in day-to-day operations.

The service provider (or relevant practices like deployment, request fulfillment, etc.) is responsible for provisioning the service, not the customer.

Now, mapping that to the options:

A. Authorizing the budget for the serviceThis is the responsibility of the sponsor role, not specifically the customer role (though one person may sometimes act as both in practice).

B. Provisioning the serviceThis is the responsibility of the service provider, not the customer.

C. Defining the requirements for the service ✅This matches the ITIL 4 description of the customer role: the customer defines requirements and is accountable for service outcomes. Therefore, this is the correct answer.

D. Using the serviceThis describes the user role, not the customer role (even though a person could be both customer and user in some real-world situations).

ITIL 4 Foundation: Definition of service consumer roles – customer, user, sponsor