The correct answer is: A. to the supply side of the current coil.
A wattmeter is an instrument used to measure the power in an electrical circuit. It consists of two coils, a current coil and a pressure coil. The current coil is connected in series with the load, and the pressure coil is connected in parallel with the load. The power is then calculated by multiplying the current and the voltage.
In a low power factor wattmeter, the pressure coil is connected to the supply side of the current coil. This is because the current coil is designed to measure the current in the load, and the pressure coil is designed to measure the voltage across the load. If the pressure coil were connected to the load side of the current coil, it would measure the voltage drop across the current coil, which would not be the same as the voltage across the load.
Option B is incorrect because the pressure coil is not connected to the load side of the current coil. Option C is incorrect because the pressure coil cannot be connected in any of the two meters at connection. Option D is incorrect because the pressure coil is connected to the supply side of the current coil.