We have to find the force of gravity of an object that has a mass of 20 kg and then to choose the correct answer. The formula for the force of gravity is: F = m * g, where m is the mass of an object and g is the acceleration of the gravity ( on Earth : g = 9.81 m/s^2 ). F = 20 kg * 9.81 m/s^2 = 196.2 N, or approximately 196 N. Answer: A. 196 N.