The Banks family lived at number a) fifty, b) ten, c) seventeen.

The text states, "The Banks family lived at number a) fifty, b) ten, c) seventeen." This presents the possible street numbers where the Banks family lived. To determine the correct answer, one would need to refer to the original text from which these questions were extracted. Without that context, it's impossible to choose definitively between fifty, ten, or seventeen.

If the intent is to list the options provided, then the answer is the list.

Answer: a) fifty, b) ten, c) seventeen