Correct Option: B

When the resultant of all forces acting on a particle is zero, the particle is in equilibrium. The equilibrium of a particle to which a single force is applied may be maintained by the application of a second force that is equal in magnitude and direction, but opposite in sense, to the first force. This second force, which restores equilibrium, is called the equilibrant. Hence, the minimum number of forces to keep a particle in equilibrium is two.