In Wikipedia’s definition of multiplication, they indicate the first factor is the number of copies and the second is the number being repeated.
Why Was 5 x 3 = 5 + 5 + 5 Marked Wrong
Brett Berry

Funnily enough, in Italian it's the opposite. Wikipaedia reads: "Dati due numeri interi positivi "n" e "m", detto il primo “moltiplicando” ed il secondo “moltiplicatore”, la definizione di moltiplicazione non è altro che:

ovvero “addizionare il numero "n" per "m" volte.”

I would argue that the question is ill posed. Had it read: "given a muliplicand of 3 and a multiplier of 5, use the repeaded addition strategy to calculate the result." I would agree to your conclusion.

As it stands, it's just a frustrating example of unclear requirements since it doesn't communicate the importance of the role given to the two terms.

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