foul or not?

[Brian Watson]

I think you answered your own question, if there is contact, and in YOUR opionion B was put at a disadvantage, then you have a foul, if not let it go.

I guess my brain if fried, becasue I cannot picture how I would call a foul on this play, unless there was displacement. Simply putting yourself between the defender and the person with the ball is not a foul, even if you move to maintain that screen, unless there is contact that puts the defender at a disadvantage. If you maintain a space that let's B adjust, I would let minor contact go.