I'm very confused. The Blender documentation states :
The Mirror modifier mirrors a mesh along its local X, Y and/or Z axes, across the Object Origin.
Referring to the image, A is the result I would like to see, but B is what I'm getting. Both the origin and the local axes are in the right place but it still appears to be mirroring across the global axes.
I've also attached the Transform and Modifier settings for B.