Where C is the loop with z=2
with a clockwise orientation when viewed from above.
As usual, I have trouble with the third dimension. I have a problem like this without the third dimension, and I have problems with the third dimension but other shapes (parabola, etc). I'm confused with this one.
Edited: can you show me both clockwise and counterclockwise orientations? I'm not really following how to differentiate that part.