What is the relative minor key of C major?

The relative minor key of C major is A minor. This relationship is established by the fact that the relative minor key is based on the sixth degree of the major scale. In the case of C major, the notes are C, D, E, F, G, A, and B, leading to A being the sixth note.

When you move from the C major scale to A minor, you are essentially using the same key signature (no sharps or flats), making A minor the relative minor key. This connection highlights the natural relationship between major and minor scales within the same key signature. Understanding this concept is crucial in music theory as it illustrates how scales are interrelated.

The other options represent different minor keys that are not directly related to C major through their key signatures.