Which of the following statements is/are correct about work?

In a certain reference frame W_{pscudo force} + W_{consevative force} + W_{non –cons force} + W_{other forces} = $\Delta K$

Work done by friction is always negative

Work done by force is defined as the dot product of the force and the displacement of the point of application of force.

Work done by conservative force in moving a body from A to B= Potential energy of body at A- potential energy of the body at B.