What API is utilized to create a new schema?

Utilizing the Schema Registry API for creating a new schema is the correct approach because the Schema Registry specifically handles the management of schemas within the Adobe Experience Platform. This API provides the functionality to define and register new custom schemas while specifying details like fields, data types, and relationships.

By focusing on the specific endpoint for creating a new custom schema, it ensures that the schema is properly defined within the system, adhering to the schema management protocols established in Adobe Experience Platform. This action allows for seamless integration and data governance.

Other options might mention the creation of schemas but are either not focused directly on customizing schema creation or refer to services that don't specifically cater to schema registration, making option B the most accurate and relevant choice in this context.