Answer: GMINOR

AnswerCrossword Clue
GMINORKey of Tchaikovsky's Symphony No. 1
GMINORKey of Mozart's Symphony No. 40
GMINORKey with two flats
GMINORKey used often by Mozart
GMINORKey of Mozart's 40th symphony
GMINORKey of much of Verdi's "Requiem"
GMINORTwo-flat key
GMINORKey of Mozart's Symphony No. 25
GMINORKey of Mozart's Symphony No. 25 or 40
GMINORMusical key with two flats