The section that will rotate is a triangle with base b = 5 and height h = 3.
The base is perpendicular to the axis of rotation, while the height is parallel.
Also, the side represented by the height is at a distance of 4 units from the axis of rotation.
We can see that the only graph where the triangle is at a distance of 4 units is Option D. All the others are too close the axis.
Answer: Option D