7. One circuit contains three 1.5 V batteries are connected in series to a light bulb. Another circuit has one 1.5 V battery connected in series to a light bulb. Which of the following statements is true? a. Three batteries provide more voltage than one battery.
b. The light bulb becomes brighter when three batteries are used.
c. The three batteries provide 4.5 V of electricity.
d. All of the above statements are true.