Tough round for me this time on first inspection, between Hidden Agenda, Natural Formations and Smooth Ride
However after some contemplaton Hiden Agenda gets my vote as this picture looks very natural and has good colour and contrast. I also like the perspective in the picture as well, and how the focus is on the model, with the foreground and background out of focus.
I might have gone for Natural Formations had you been able to see more of her face. The position of her head and shadow make it less favourable for me
Smooth ride is nice, but is jus the model that is nice with her pose and not the whole picture...it looks too "magazine shot/porno mag" IMO