Which of the following statements is true regarding the duties of the assistant referee?

The statement that all duties of assistant referees are subject to the discretion of the referee is correct because it highlights the hierarchical structure of officiating in soccer. While assistant referees have specific responsibilities, such as signaling for offside or indicating when the ball has gone out of play, their actions and decisions ultimately support the decisions made by the center referee. The center referee has final authority on all calls, including those that the assistant referee may make or signal. This collaborative dynamic ensures that the match is officiated in a manner that is consistent with the Laws of the Game but still remains under the central referee's control.

In contrast, the first statement suggests that all duties are rigid and unchangeable, which overlooks the collaborative nature of officiating. The third statement incorrectly claims that assistant referees share the same authority as referees, which misrepresents the roles they each play in the match. Finally, the fourth statement implies that assistant referees cannot make decisions on fouls, while they can indeed bring attention to fouls or misconduct they observe, although the final decision lies with the referee.