What Do We Know About the Direction in Which Spiral

What do we know about the direction in which spiral galaxies rotate?

A) We don't know anything; they rotate too slowly for us to have seen any motion in the time since galaxies were discovered.
B) They don't rotate; if they did, the spiral pattern would soon disappear. This is the winding dilemma.
C) The ends of the arms trail the rotation (point back) .
D) The ends of the arms lead the rotation (point forward) .