Which instrument sounds down a major sixth plus one octave from written treble?

• A. Eb contra alto bass clarinet
• B. Bb soprano clarinet
• C. Oboe
• D. Bb soprano sax

Answer: (A)

Transposition differences between written and sounding pitches are what this item tests. Sounding down a major sixth plus one octave equals a major thirteenth. The instrument that matches this exactly is the Eb contra-alto (contrabass) clarinet, which is written in treble but sounds a major thirteenth lower than written. In other words, written notes sit up by a major sixth and an octave to produce the concert pitch.

That’s why this instrument is the best fit: its transposition distance is the large interval described, unlike the oboe (which sounds as written) or the other options whose transpositions are much smaller (a second or a ninth, not a thirteenth).