Dead on, Legacy. My rationale, written last night, is a bit more wordy (a slight little bit more depth for those learning), but says exactly the same thing. We'd have been good on a crew together.
Ruling:
Option 1 (plausible)
B, Free Kick, B-20, 2:05 (4), free kick timing (25). A=19, B=21.
When the ball became dead behind B’s goal line (when it contacted the pylon), the impetus on the ball was with B49’s (illegal) batting of the ball. Since Team B is, then, responsible for the ball being dead behind their own goal line, the natural result of the down is a safety, 2 points for Team A, with a free kick by B from the B-20 to follow. Team A would need to decline the penalties for the roughing the passer foul by B99, and the illegal batting foul by B49. They might choose this option, hoping to get the ball with the ensuing free kick, and advance into position to kick a game winning field goal.
Option 2 (most likely)
A, 1/10, B-12 ½, 2:05 (4), snap (25), A=17, B=21.
Team A could refuse the safety, decline the 10-yard penalty for the illegal batting foul from the end of the related run, and accept the 15-yard penalty for the roughing the passer (RPS) foul. The 15-yard penalty for the RPS foul would actually be penalized ½ the distance from the end of the last run, which is the spot of A88’s fumble, the B-25, taking the ball to the B-12 ½. The yardage yields a first down (although the penalty also includes a first down).
Note that the RPS penalty may be added to the last run IF there was no change of team possession DURING the down. There was no change of possession during the down; thus, Team A will have the penalty enforced at the end of the last run.
Due to either the ostensible safety, or the completion of the penalty, the play clock is set to 25 seconds, and will start on the referee’s signal. Due to the ostensible safety, the game clock will start on the snap.
Team A would most likely accept this option, putting them in good field position to score the game winning touchdown. But, with a 4-point score differential, they would need a touchdown. A field goal would leave them 1 point behind, and virtually force them to attempt an onside kick, in hopes of getting the ball legally, and advancing enough score a game winning field goal, all of which would be much harder to accomplish. That's why it is the Coach's choice.
