Which statement describes the mapping? A. The mapping represents y as a function of x, because each y-value corresponds to exactly one x-value. B. The mapping does not represent y as a function of x, because two of the x-values correspond to the same y-value. C. The mapping represents y as a function of x, because each x-value corresponds to exactly one y-value. D. The mapping does not represent y as a function of x, because there are more x-values than different corresponding y-values.