test question

[ggk]

i'm reviewing an old ncaa test. i'm bit confused by the answer and would appreciate any help.

q.
r2 and r1. F1 attempts a pick-off at 1st. R1 is obstructed on his way back to the bag. the throw gets by F3 and rolls down the RF line. R1 advances to 2nd. R2 rounds 3rd and heads for home and is thrown out at the plate.

answers ( you can choose one or more)
a. ball remains alive
b. play should be killed at time of obstruction.
c. R2 should have been awarded 3rd and R1 awarded 2nd.
d. R2 is out

what do you think? remember - ncaa.
thanks.