What is the upper range limit of the organ?

The upper range limit of the organ is generally considered to be C7. This is due to the instrument's design and the typical repertoire that it serves, which can include everything from liturgical music to contemporary compositions. The register of the organ is capable of producing a wide array of pitches, but C7 is recognized as the point where most playable organ pieces for experienced players usually end. The organ's extensive range contributes to its ability to perform complex and varied musical works, making C7 a fitting designation for its upper limit.

Other choices, such as C6, C8, and B7, do not correspond with the widely accepted understanding of the organ's range. C6 falls within a lower register, while C8 exceeds the conventional limits, which are generally not reached in practical organ performance. B7 is closer to the upper limits than C6, but it still does not reach the recognized endpoint of organ capabilities as C7 does.