The correct option is Cloud service broker.

A Cloud service broker acts as an intermediary that coordinates and supervises interactions between the organization that purchases cloud offerings and the company that delivers them. A broker can negotiate contracts and service level agreements on behalf of the purchaser and can provide aggregation, integration, governance, and consolidated billing so the buyer has a single point of contact rather than dealing with multiple providers.

Managed service provider is not correct because a managed service provider typically operates or manages IT services for a customer rather than acting as a neutral intermediary that brokers relationships across multiple cloud providers.

Cloud service customer is not correct because the customer is the purchaser or consumer of cloud services and is not the party that coordinates or supervises interactions between purchaser and provider.

Cloud service provider is not correct because the provider is the company that delivers the cloud services and does not perform the purchaser side coordination role that a broker performs.

Full AWS Practitioner Certification Question