[crazy voyager]

This is a violation by the shooter and therefore B gets the ball.
If two rebounders (one from each time) had violated we would have a jump ball.
43.3.1 If a violation is committed by a free-throw shooter:
• Point, if made, shall not count.
• Any other player’s violation, which occurs immediately before, at approximately the same time as, or after the violation committed by the free-throw shooter, shall be disregarded.

43.3.3 If a free throw is not successful and the violation is committed by:
• A team-mate of the free-throw shooter on the last or only free throw, the ball shall be awarded to the opponents for a throw-in at the free-throw line extended unless that team is entitled to further possession.
• An opponent of the free-throw shooter, a substitute free throw shall be awarded to the free-throw shooter.
• Both teams, on the last or only free throw, a jump ball situation occurs.