Answer: B
Explanation:
The graph only has a horizontal asymptote.
An asymptote means that the line will get closer and closer to a number, but never cross it. So in other words, get infinitely close to a number. In this case, the horizontal asymptote is at y=3. That means the line won't go any further up than 3. So the range won't go higher than 3. But we don't need the range.
The other side of the line, isn't getting super close to anything. It is only going diagonally, as far as we see it. Since it doesn't stop at any number, and the other side is going infinitely towards the right, unlike how it isn't going infinitely up, the domain goes infinitely to the and left.
Therefore, the domain would be -∞ < x < ∞