Good luck with the interview, if they ask you that question and I'm sure they will. Tell them that you would like to work for a stable company that has room for you to advance from a entry level position to hopefully a management level job. They also would be looking for what type of personality you have and how well you interact with others. Let them know that your a dependable person that you don't mind working on weekends (hopefully that applies).
Let us know how it goes! I'm sure you'll do fine