A good way to remember the diatonic chords in a minor scale is to remember that the minor starts on the sixth note of its relative major's scale. So the one in the minor scale is minor because the 6 is minor. Then it follows the pattern of the major scale on--starting from the 6 which is minor, you have MINOR-diminished-major-minor-minor-major-major. When you remember that, it is easier to match chords to the bass in a minor key. The chords of the major scale(which in this case is C) are; major minor minor major major MINOR diminished. See the relationship? The chords are not always used as listed, but most of the time, they are.