Which instrument sounds down a major sixth from written treble?

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

Answer: (B)

Transposing instruments use written pitches that don't match concert pitches. For an instrument that sounds a major sixth lower than written treble, the one in E-flat (the alto sax) fits this description. When you read a written C on an Eb alto sax, it sounds concert E-flat, which is nine semitones lower—a major sixth down. So the instrument is notated a major sixth higher than the concert pitch you want to hear.

The other options don’t fit because they transpose differently: a Bb soprano clarinet sounds a whole step lower than written; the oboe sounds in concert pitch (no transposition); a Bb tenor sax sounds a much larger interval, effectively down a ninth plus an octave.