If A4 is injured and in an offside position when A3 scores, what is the referee's decision?

When a player who is in an offside position becomes involved in active play, their actions can affect the outcome of a goal. In this scenario, A4 is injured but still in an offside position when A3 scores. However, since A4 is not interfering with play or gaining an advantage from their position, the offside rule does not come into effect. The key aspect here is that an injured player who is not playing the ball, interfering with an opponent, or gaining an advantage does not influence the validity of the goal scored by A3. Therefore, the referee would allow the goal because A4's offside position does not warrant disallowing the goal under these specific circumstances.