newtonian mechanics - Work done by action-reaction pair of tension

Work done by action-reaction pair of tension force on a system is zero if the string is inextensible I am trying to understand this statement taking the following arrangement in consideration. He

Chapter 1: Newtonian Mechanics

Newton's 3rd Law-Action Reaction pairs-Inclined Plane

4.4 Newton's Third Law of Motion

newtonian mechanics - Pulley-rope tension question - Physics Stack Exchange

newtonian mechanics - Work done by action-reaction pair of tension - Physics Stack Exchange

newtonian mechanics - Confusing statement about tension - Physics Stack Exchange

Newton's third law of motion 1 Force 2 - ppt download

6.1 Solving Problems with Newton's Laws

newtonian mechanics - Is there a general rule for determining the direction of tension force? - Physics Stack Exchange

Lesson Explainer: Connected Particles