Collision at First Base

[Dakota]

ASA, NFHS, NCAA, ... pick your poison...

OK, for you counting-angels-on-the-head-of-a-pin types:

R1 on 1B. B2 slaps the pitch toward the right side of 2B and F4 fields the ball with her bare hand, runs toward 2B, and dives toward 2B. In the base umpire’s judgment, F4 has control of the ball and is holding the ball securely. F4, with her hand outstretched, and R1 are both converging on 2B at about the same time.

a) F4 dives on 2B and touches it with the ball. As soon as F4 touches 2B with the ball, the ball rolls loose.
b) F4 dives on 2B and touches it with the ball. As soon as F4 touches 2B with the ball, R1 sliding in, and contacts F4's hand, and the ball rolls loose.
c) F4 dives as R1 is sliding into 2B. F4 touches R1's foot with the ball before she reaches 2B. As soon as F4 touches R1 with the ball, F4's hand contacts the base, and the ball rolls loose.
d) F4 dives as R1 is sliding into 2B. F4 touches R1's foot with the ball before she reaches 2B. As soon as F4 touches R1 with the ball, the ball rolls loose.

Rulings? Same, different, why?