What signal begins the 25-second count by the referee?

The signal that begins the 25-second count by the referee is the "Ready for play" signal. This signal indicates that the offensive team has 25 seconds to snap the ball. It is crucial for maintaining the pace of the game and ensuring that teams adhere to the time constraints on offense.

When the referee signals "Ready for play," it signifies that the team has completed whatever preparations they need to make, whether that's substituting players, discussing strategies, or lining up for the next play. This countdown ensures that games keep moving along efficiently and that teams do not take an excessive amount of time between plays.

The other options pertain to different situations in a game. For instance, the "Set for play" signal is related to ensuring that both teams are prepared for the snap, while the "End of quarter" signal indicates the conclusion of one quarter of play. The "Timeout signal" is related to stopping the game clock and does not initiate the 25-second count. Understanding the specific role of the "Ready for play" signal helps clarify the overall structure and flow of the game.