A student notices that producing 1.00 g of Al requires a considerably larger electric charge than producing 1.00 g of Cu under identical conditions. Which of the following best explains this observation?
a) Aluminum has a lower molar mass than copper.
b) Aluminum ions require three electrons per ion, whereas copper(II) ions require only two.
c) Copper has a higher reduction potential than aluminum, so less charge is needed to deposit copper.
d) Because aluminum ions are triply charged, fewer aluminum ions must be reduced for 1.00 g of metal, so less charge should be needed.