Possible Clues:

• It's a bit higher than a D
• Key beside D
• Key of Beethoven's "Emperor" concerto
• Key of Beethoven's 'Emperor' concerto
• Another name for D sharp
• Key for Tchaikovsky's '1812 Overture'
• Key near D
• Key for a high-pitched clarinet
• Ti, in F minor
• D sharp sound-alike