To know the unit of measurement of the final answer, you have to use the technique of dimensional analysis. In this technique, you strip off the magnitudes of the units to do away with the calculations. You have to make sure first that you end up with the final answer. So, for this problem, you are given two parameters: force and surface area. Thus, you focus on the units of force and surface area. One of the units must be in Newtons to represent the force, and the other should be in square units to represent the area. From the choices given, the answer would most likely be letter B.
This is the other choices include units like cubic units and kilograms which pertain to volume and mass, respectively. None of these have to do with force and surface area.
