D-flat minor
Because it has so many flats, D minor is usually written as its enharmonic equivalent of C minor. For example, Mahler's thematic motif "der kleine Appell" ("call to order") from his Fourth and Fifth Symphonies is written in D minor in Symphony No.4, but in his Symphony No. 5 it is in C minor. In the Adagio of his Symphony No. 9 a solo bassoon theme appears first in D minor, but comes back two more times notated in C minor. The Adagio of Bruckner's Symphony No. 8, also has phrases that are tonally in D minor but written as C minor.