A 6 V battery is connected to a 10 Ω resistor. Which of the following arrangements will correctly measure the potential difference across the resistor?
a) Voltmeter connected in series with the resistor; ammeter in parallel with the resistor.
b) Both voltmeter and ammeter connected in parallel with the resistor.
c) Voltmeter connected in parallel with the resistor; ammeter in series with the resistor.
d) Both voltmeter and ammeter connected in series with the resistor.