How should a man cross the river in order that he takes (i) shortest time and, (ii) shortest path?

(i) Shortest time : To cross the river by the shortest time, he has to be rowed perpendicular to the river.
As a result of the river velocity the person will reach a point say C from A. (drawn the current).

(ii) Shortest path : To cross by shortest path, i.e., from A to B the boat should be rowed at an angle