Please help me I will give out extra points and the brain thing. image below
 Which statement about this mapping is true?
 The mapping does not represent y as a function of x, because 3 x-values are related to 1 y-value.
 The mapping does not represent y as a function of x, because there are more x-values than related y-values.
 The mapping represents y as a function of x, because each y-value is related to exactly one x-value.
 The mapping represents y as a function of x, because each x-value is related to exactly one y-value.