A hermaphrodite caliper, also called an odd-leg or jenny caliper, is a marking-out tool used to scribe lines parallel to an edge and to find the centre of round or flat stock, especially where working space is confined.

Its distinctive feature comes from having two unlike legs, which is where the name comes from.

One leg ends in a sharp, straight scriber point that marks the metal, while the other leg is bent inward to form a caliper jaw that hooks against and rides along the edge of the work.

Running the bent jaw along the edge keeps the point at a fixed distance from it, so the scribed line stays parallel to that edge.

Two identical pointed legs (option 2) would make it a divider, used for stepping distances, not for gauging from an edge.

A flat measuring edge (option 3) or two straight parallel legs (option 4) do not match its build, since one leg is always a bent jaw and the other a point.

This mixed pair of legs is exactly what sets it apart from dividers and ordinary calipers.

Hence, the answer is One leg ends in a pointed tip while the other has a caliper jaw.