This question is designed to be answered without a calculator.

Which of the following shows a function with a non-differentiable point due to a vertical tangent?

On a coordinate plane, a line starts at open circle (negative 1, 2) and decreases through (negative 3, 0). A line starts at closed circle (negative 1, 3) and decreases through (2, 0).
On a coordinate plane, a line decreases through (negative 3, 4) to vertex (negative 1, 2) and then increases through (1, 4).
On a coordinate plane, a curve goes through (negative 4, 4) and decreases to (negative 1, 2), and then curves up through (2, 4).
On a coordinate plane, a curve goes through (negative 2, 1), curves through (negative 1, 2), and then curves through (0, 3) into quadrant 1.