Hi Amy. Having experience from both sides of the equation (😊), I think that the best position depends on my partner for A, B or C. For example, cowgirl can be fabulous if he is well endowed and fit, but otherwise the geometry doesn't work as well. Partner's enthusiasm for the encounter and the position can really impact how enjoyable it is of course. I can find a lot to enjoy if there is a receptive partner. Also, mixing up positions can be great to.

Not a clear answer for you but I really don't have a preference without the partner.