Correct option is B
In a dynamometer wattmeter, the fixed coil is known as the
current coil.
The current coil carries the load current, and it is typically connected in series with the load.
The moving coil, often referred to as the pressure or voltage coil, is connected across the load and measures the voltage.
The interaction between the magnetic fields of the fixed current coil and the moving voltage coil allows the wattmeter to measure power.
