I agree with the "have to see it" opinions. At first, I wanted to say incomplete, but after reading all the posts, I'm beginning to think differently. I do believe the hit by B to be important. For example, if this was a diving catch on the boundary, and A got a foot down, pulled the ball in, and as he fell to the ground the ball popped out, I would have incomplete pass for failure to maintain control. But, if he has one (or two) foot(feet) down, has already established control, and then B comes in and does something to cause the ball to come out, (including, but not limited to a hit, or a strip) then I would have a TD.