A function can have many x values for a given y value and still be a function but it cannot have many y values for a given x value. You can easily test this by graphing the equation and doing the vertical line test by seeing if a vertical line will intersect the graph only once at all x values, if it passes it is a function. In short what you have here is a function
I would go with football or hallway. If you choose footbal you would probably get a more random demographic but you might not get 200. If you choose hallways you could get 200 so hallway is probably more likely
