Which of the following statements about the pinacol rearrangement are correct?

1. AAn alkene is formed first and is then hydrated to give the ketone.
2. BThe hydroxyl lost as water is the one whose departure gives the more stable carbocation.
3. CThe last step is loss of a proton from a protonated carbonyl compound.
4. DThe migrating group moves with its bonding electron pair to the adjacent cationic carbon.