Offense or Defense? Basketball?

So I was teaching 5th grade today about the difference between offense and defense.  When we started the game I asked each team on the courst what they were playing.  Now, what do expect the answer to be, offense or defense, right?  Well, some genius blurts out "Basketball"!  Really????  What gave it away to bright orange ball or the fact that we have been working on it for the last month?  This is they type of crazy things I hear on a daily basis.  But, hey it sure makes the day a lot more fun!