what are all the dominant seventh chords?
c7, c#7, d7, d7, d#7, e7, e7, f7, f#7, g7, g7, g#7, a7, a7, a#7, b7, b7
which chords have a minor seventh as e?
f7, f#7
of those, which has a perfect fifth as c#?
f#7