The initial kinetic energy of the boat and its rider is

After Sam stops it, the final kinetic energy of the boat+rider is

because its final velocity is zero.
For the law of conservation of energy, the work done by Sam is the variation of kinetic energy of the system:

where the negative sign is due to the fact that the force Sam is applying goes against the direction of motion of the boat.
Direction and Strength can be measured of force
Answer: it will move to the left
Explanation: i remeber doing this
I believe the answer is the fourth one, hope this helps