For the measurement of potential difference in an electric circuit, a potentiometer is preferredover a voltmeter because the

Explanation

The correct answer is that a potentiometer does not take current from the circuit. This characteristic allows it to measure the potential difference without affecting the circuit's current, leading to a more accurate measurement. In contrast, a voltmeter draws a small current from the circuit, which can alter the potential difference being measured.Option A is incorrect because cost is not the primary factor for choosing a potentiometer over a voltmeter for measuring potential differences. Option B is incorrect because sensitivity is not the issue here; it's about the accuracy of the measurement without affecting the circuit. Option D is incorrect as well because although internal resistance matters, the key factor is that a potentiometer doesn't draw current from the circuit, unlike a voltmeter.