Torque Balance for Equilibrium Steps:

• Identify the pivot at the bar's midpoint (1.2 m from each end).
• Calculate torque for each weight: τ = F × perpendicular distance from pivot (using diagram values for F and d).
• Sum clockwise torques and anticlockwise torques separately; net torque = |anticlockwise - clockwise| = 40 Nm anticlockwise.
• Applied couple provides equal opposite torque: 40 Nm clockwise for zero net torque and equilibrium.

Why A is correct:

• Net torque from weights is 40 Nm anticlockwise; couple must exert 40 Nm clockwise to satisfy τ_net = 0 (principle of moments).

Why the others are wrong:

• B: Incorrect direction; anticlockwise couple would increase imbalance.
• C: Wrong magnitude; unbalanced torque is 40 Nm, not double.
• D: Both magnitude (80 Nm) and direction (anticlockwise) fail to balance the net torque.

Final answer: A