A man is standing on a boat in still water if he walks towards the show the boat will

A.)move away from the Shore B.)remains stationary C.) move towards the shore or D.)sink

a) move away from the shore

because
Initially, the total momentum was zero and after the man starts moving, the total momentum should still be zero (law of conservation of momentum-). So, the boat will move in the direction opposite to the direction of motion of the man.