The correct answer to this question is B, Volt. V is the symbol for volt. This measurement is an SI unit, which is used to measure the difference between force. The measurement is named after Alessandro Volta, who was a physicist.
It was named after him because he was the creator of the voltaic pile, which was the first chemical battery. Almost all electronics run off a battery, and those batteries have voltages.
For example, in remote controls, alkaline batteries are used. Single alkaline batteries that can not be recharged have a voltage of 1.5. Mercury batteries have a voltage of 1.355V.