Which graph represents y as a function of x?

I will give 100 points for help because I feel that's a good trade

Which graph represents y as a function of x I will give 100 points for help because I feel thats a good trade class=
Which graph represents y as a function of x I will give 100 points for help because I feel thats a good trade class=
Which graph represents y as a function of x I will give 100 points for help because I feel thats a good trade class=
Which graph represents y as a function of x I will give 100 points for help because I feel thats a good trade class=