Remember that the range is the set formed by y-values, that is, the dependent variable elements.
If you think this through, you would deduct that a power cannot be equal to zero or a negative number. All powers are always positive and greater than zero, because the least power that can exist is equal to one, which is .
Therefore, the right answer is , because that's the restriction of exponential expression by definition.
So If you graph the function, you'll see that it never actually crosses the y axis into the third or fourth quadrant, the quadrants where all y values become negative.
