The correct answer is infinite (option D). An ideal voltmeter is designed to have infinite resistance. This characteristic ensures that when connected across any points in an electrical circuit to measure voltage, it draws negligible current from the circuit. Drawing no current means that the voltmeter does not alter the voltage it is supposed to measure. In practical terms, real voltmeters have very high resistance, typically in the range of millions of ohms, to minimize the loading effect on the circuit being measured. However, an ideal voltmeter conceptually has infinite resistance, ensuring accurate voltage measurement without disturbing the circuit. This property distinguishes a voltmeter from an ammeter, which has low resistance to measure current flow. Understanding these distinctions is crucial for correctly applying and interpreting measurements in electrical circuits and systems.