A man of mass 60 kg is standing on a boat of mas 140 kg, which is at rest in still water. The man is initially 20 m away from the shore. He starts walking on the boat for 4 s with a constant speed of 1.5 m/s .owards the shore? What will be his final distance from the shore?

A. 15.8 m
B. 4.2 m
C. 12.6 m
D. 14.1 m