"A" is running with a velocity of 13 kmph in the direction of the river along the river bank. A boat which is at a distance of 12 km from "A" crossed him in 40 minutes by rowing against the flow of the river. If the river is flowing with a velocity of 1.5 kmph, then what is the velocity of the boat?
A 6.5 kmph
B 5 kmph
C 4.5 kmph
D 4 kmph