SLA (Service Level Agreement) tiers are created and managed within the API Manager component of the Anypoint Platform. API Manager is used to govern and secure APIs that are deployed and running. It allows administrators to apply policies, such as rate limiting or throttling, by defining different SLA tiers (e.g., Gold, Silver, Bronze). These tiers can then be requested by and granted to client applications, enforcing consumption limits at runtime.

A. Exchange is a repository for discovering, sharing, and reusing API specifications and other assets, not for managing runtime policies like SLAs.

C. Anypoint Studio is the IDE for designing and developing Mule applications. Runtime governance and policy management are performed in API Manager.

D. RAML is a specification language used to design an API's contract. It does not define or enforce runtime operational policies like SLA tiers.

MuleSoft Documentation, "API Manager". Describes its function: "Use API Manager to manage, govern, and secure your APIs... Apply predefined or custom policies to your APIs to control access and traffic." (docs.mulesoft.com/api-manager/2.x/)

MuleSoft Documentation, "SLA-Based Policies". Explains, "You can apply the Rate Limiting and Throttling policies to specific API methods and resources, and you can also configure the policies to enforce different service-level agreements (SLAs) for each of the API’s clients." This configuration is done in API Manager. (docs.mulesoft.com/api-manager/2.x/sla-based-policies)