In the context of the function \( C(n) = 12n + 5 \), the variable \( n \) represents the number of necklaces ordered. Therefore, \( C(3) \) represents the total cost to order 3 necklaces, including the flat rate shipping charge.
To evaluate \( C(3) \): \[ C(3) = 12(3) + 5 = 36 + 5 = 41 \] So, \( C(3) = 41 \) means that it costs $41 to order 3 necklaces.
In terms of inputs that do not make sense in this scenario, any negative value for \( n \) (like \( n = -1 \) or \( n = -5 \)) would not make sense because you cannot order a negative quantity of necklaces. Additionally, a non-integer value (like \( n = 2.5 \)), if it is not permissible in the context, can also be considered nonsensical since you can't order a fraction of a necklace. Thus, inputs like \( n < 0 \) or non-integer values (if not specified explicitly allowed in the scenario) would not make sense.