One of the forces acting on a particle is conservative then which of the following statement(s) are true about this conservative force : 

1. Its work is zero when the particle moves exactly once around any closed path.
2. Its work equals the change in the kinetic energy of the particle
3. Then that particular force must be constant. 
4. Its work depends on the end points of the motion, not on the path between.

1 and 4

1. The work done by a conservative force is zero.
2. The conservative force may or may not be constant.