Which of the following is true with regard to voltmeters?

Voltmeters are designed to measure the potential difference between two points in an electrical circuit. When connected in parallel with the component being measured, the voltmeter ensures that it measures the voltage across that component directly. This parallel connection allows the voltmeter to have minimal impact on the circuit, as it draws very little current due to its high impedance.

The other choices present some misunderstandings about voltmeter usage. For instance, polarity is crucial in DC measurements because connecting the leads incorrectly can not only give you the wrong reading but may also damage the meter. It's also not correct to state that the negative lead should connect to the high potential end; the negative lead should be connected to the lower potential end to ensure accurate readings. Lastly, while working with a range selection switch, it's generally advisable to start with the highest setting and work downwards to avoid overloading the meter, not the other way around.