Consider the following statements for system of forces :

I. Two or more forces that act at the same point are called coplanar forces.

2. Two or more forces whose directed arrows lie in same plane are called concurrent forces.

3. Varignon’s theorem states that ‘the moment of several concurrent coplanar forces about any point O in their plane equals the moment of their resultant about the point O.

4. Lami’s theorem states that if a body is in equilibrium under the action of three forces, each force is proportional to the sine of angle between the other forces.

Which of the above statements are correct ?