The only answer is choice D) 6
Recall that the range is the set of possible y output values of a function. In other words, its the list of y coordinates for every point on the function curve.
In this case, the horizontal line has EVERY point on it with a y coordinate of y=6. Two such points are (0,6) and (2,6). No other y value is possible. No matter what x value we plug in, the output is always y = 6
Side Note: the domain appears to be from x = -3 to x = 5
