DMAJ

Set to 3 different clues across 3 published puzzles, most often “Key with two sharps: Abbr.” — The New York Times, Tuesday, 24 May 2011.

4 letters

Every clue on record, most used first

Key with two sharps: Abbr.once
The New York Times — Tuesday, 24 May 2011
Key of Mahler's Symphony No. 1: Abbr.once
The New York Times — Friday, 17 April 2009
Key of Pachelbel's Canon: Abbr.once
The New York Times — Thursday, 10 January 2008