Inbounder possession

[Jurassic Referee]

Blow the whistle,wave off the 2nd. B basket,and then let A re-do the throw-in(and run the end line,too).Rule that the ball was never truly at the disposal of team A for the throw in.That's the purpose and intent of the rule.It's similar to the case of a free thrower fumbling the ball when the administering official tosses it to him.