Work = force x distance. In units, Joules = Newtons x meters.
So: Work = 50 Newtons x 3 meters
Work = 150 joules. Answer D is correct
FYI - to ace physics, you should learn to identify these values using their fundamental units:
Force = Newtons = Kg·m/s²
Work = joules = kg·m²/s²
Power = watts = kg·m²/s³
In high school physics, If you learn to arrange equations so the units work out properly for the answer, you'll get most problems correct.
