Which is the correct statement about law of polygon of forces?

• A. if any number of forces acting at a point can be represented by the sides of a polygon taken in order, then the forces are in equilibrium
• B. if any number of forces acting at a point can be represented in direction and magnitude by the sides of a polygon, then the forces are in equilibrium
• C. if a polygon representing forces acting at a point is closed then forces are in equilibrium
• D. if any number of forces acting at a point can be represented in direction and magnitude by the sides of a polygon taken in order, their resultant may be represented in magnitude and direction by the closing side of the polygon, taken in the opposite order.