Which organization is known for its non-profit mission regarding music sources?

The correct choice reflects the organization that is specifically dedicated to documenting and providing access to information about music sources from various cultures and time periods. The Repertoire International des Sources Musicales (RISM) is a non-profit organization that focuses on the identification and documentation of music sources. This includes rare manuscripts, printed music, and other musical documents, making it a vital resource for musicologists, historians, and educators interested in the study of music.

Unlike the other options, which serve different functions—such as providing cataloged online articles about music, offering encyclopedic detail on popular music, or compiling an encyclopedia focused on world music—RISM’s core mission is specifically focused on the preservation and accessibility of musical sources, supporting research and education within the global music community. This singular focus underscores its role as a unique non-profit organization dedicated to the field of music studies.