This one probably works best just to start with how old he is now: that is, if Aiden was 14 years old 14 years ago, that means he is now 28 years old.
Then, we just need to think of c as if it's a normal integer number: for example, if we wanted to know how old he was five years ago, we would say he was 28 - 5 = 23.
So in this case, it's as simple as saying that he was 28 - c years old.
Answer C.
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