Lady in red

well she is the best model out of these 3... She looks natural for the camera and comfortable posing to you. First one looks kind of a tense, altough her first photo is better than second still.
On the second shot she has hands crossed and the pose is kind of a closed, even a bit agressive in my opinion.
Your second model, photo no 3 gives a feeling of a random shot. This pose would work on a little smoother surface... For example on a rock or somethig.