Three men and two women crossed a river in a boat that held only two persons.

1. No women was left alone with a man at any time, as required by the women.
2. Only one person rowed during each crossing; no one rowed twice in succession, as required by the men.
3. Of those who rowed while alone in the boat, Art was the first, Ben was the second and Cal was the third.

Assuming the minimum number of crossings, who was the last to row across the river?