Answer: B
The formula used to calculate the mass of an object if the net force and its acceleration are known is m = F/a. Where Force is measured in N (newton) and it can be write as (kg * m)/ s2 while acceleration is measured in m/s2.
This equation is derived from Newton's second law of motion where the acceleration of an object is produced by a net force that is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object. So the larger the object mass the smaller the acceleration.