Deflecting Torque:
The deflecting torque is the torque that acts on the pointer of an indicating instrument and causes it to move. It is usually produced by a current or voltage flowing through a coil, which interacts with a magnetic field to create a rotational force.

Opposing Torques:
When the pointer of an indicating instrument is in motion, it experiences opposing torques that try to resist its movement. These opposing torques are necessary to ensure that the pointer settles at the correct position and provides accurate readings. The two main opposing torques are:

Damping Torque:
- The damping torque is a torque that opposes the motion of the pointer and helps to bring it to rest quickly without any oscillations.
- It is typically provided by a damping mechanism such as a vane or air drag.
- The damping torque is proportional to the velocity of the pointer and acts in the opposite direction to its motion.
- It is responsible for controlling the speed at which the pointer moves and prevents overshooting or undershooting of the desired position.
- The damping torque is necessary to ensure the stability and accuracy of the instrument's readings.

Controlling Torque:
- The controlling torque is a torque that opposes the deflecting torque and helps to position the pointer accurately.
- It is usually provided by a spring or a gravity-controlled mechanism.
- The controlling torque is proportional to the displacement of the pointer from its desired position and acts in the opposite direction to bring it back to the desired position.
- It is responsible for controlling the deflection of the pointer and ensuring that it accurately reflects the input signal.
- The controlling torque is necessary to ensure the precision and linearity of the instrument's measurements.

Conclusion:
When the pointer of an indicating instrument is in motion, it experiences opposing torques that help to bring it to rest quickly and accurately at the desired position. The damping torque opposes the motion and controls the speed of the pointer, while the controlling torque opposes the deflecting torque and positions the pointer accurately. Both torques are essential for the proper functioning of the instrument and the accuracy of its readings. Therefore, option 'B' is the correct answer.