Which of the following conditions is correct for rest of pointer in indicating instrument?

Correct option is A

$$\bullet \ \text{In an indicating instrument, the pointer comes to rest when the deflecting torque } (T_d) \text{ produced by the measurement system is balanced by the controlling torque } (T_c) \text{ produced by the control system (usually a spring or a similar mechanism).} \\[8pt]\bullet \ \text{At this equilibrium point, the two torques are equal and opposite in direction, resulting in no net torque and thus a steady position of the pointer.} \\[8pt]\bullet \ \text{Mathematically:} \\[4pt]T_d = T_c \\[10pt]\bullet \ \text{If the deflecting torque were less than the controlling torque } (T_d < T_c), \text{ the pointer would move back towards zero.} \\[8pt]\bullet \ \text{If the deflecting torque were greater than the controlling torque } (T_d > T_c), \text{ the pointer would continue to move away from zero.} \\[8pt]\text{Hence, for the pointer to rest at a stable position, the deflecting torque must equal the controlling torque.}$$​​