Two women (Amy and Beatrice) and three men (Charles, Dennis and Ethan) have to

row across a river in a small boat that can only sit two people at the most.
They want to cross the river using the least number of crossings.
b. Only one person will row the boat during each crossing.
c. The women request that no woman will be left alone with a man (or men) at any
time.
d. The men request that no one will row the boat twice in two consecutive crossings.
e. Of those who will row while alone in the boat, Charles will be the first, Dennis
will be the second and Ethan will be the third.

Who will be the last person to row across the river?