Which minor key corresponds with 4 sharps?

The minor key that corresponds with 4 sharps is F# minor. To understand why F# minor has this key signature, we can look at the structure of sharp keys.

F# minor, being the relative minor of A major, shares the same key signature. A major has three sharps (F#, C#, and G#). In the case of F# minor, it introduces one additional sharp, which is D#, bringing the total to four sharps.

Furthermore, the circle of fifths can be helpful here. F# is four steps clockwise from C, which is the key with no sharps. Each step adds a sharp, so moving from C to G (one sharp), G to D (two sharps), D to A (three sharps), and finally A to E (four sharps). The key signature of F# minor completes this progression with the inclusion of D#.

The other options correspond with different key signatures: D minor has one flat, C minor has three flats, and A minor has no sharps or flats, confirming that F# minor is indeed the correct answer.