You asked the question twice I answered it on the last one
The correct answer among the choices is option D. Density is not one of the properties included in the ideal gas law. The law is expressed as: PV=nRT. As we can see, the pressure, the volume and the temperature of the gas are included in the law.
Voltmeter is used to find the potential difference between two points.
We always connect it in parallel to the points where we need the potential difference.
Here in order to make the reading accurate we can increase the resistance of voltmeter so that it can not withdraw any current from the circuit.