The range is the set of all y-coordinates of the points in the graph.
The graph is a wavy function that has a maximum y-coordinate of 1 and a minimum y-coordinate of -1. The y-coordinates can also be all numbers between -1 and 1. Choice A. is only the two numbers -1 and 1. That is not correct since the range comprises the numbers -1, 1, and all numbers in between -1 and 1.
