If B-1 interferes with A-2's throw-in without any legal touch prior, what should be the official's ruling?

When B-1 interferes with A-2's throw-in without any legal touch prior, the proper ruling is that Team A is awarded a new throw-in. This is based on the understanding that any interference during the throw-in process, especially without a legal touch, disrupts the normal flow of the game and the rights of the team executing the throw-in.

In the case of interference, the official recognizes that Team A did not have the opportunity to complete the throw-in as prescribed by the rules, necessitating a reset of the situation. By awarding a new throw-in, it restores Team A's right to deliver the ball from the designated spot without any hindrance, thereby ensuring fair play.

This ruling also corresponds to maintaining the integrity of the game by penalizing the interference while allowing Team A to attempt their throw-in again, thereby providing a remedy for the disruption caused by Team B's actions.