An electrolytic reduction of an aqueous solution containing the trivalent ion of an unknown metal, M³⁺, is carried out with a current of 0.600 A for 40.0 min. Because of competing side reactions, only 75.0 % of the current actually contributes to metal deposition. If 0.480 g of metal is obtained, which of the following molar masses is most consistent with the experimental results?
a) 97gmol−1
b) 86gmol−1
c) 129gmol−1
d) 72gmol−1