If a team's players are not set for one second before the snap, what is the penalty?

In football, all offensive players are required to be in a set position for at least one second prior to the snap. This rule is designed to ensure fair play and allow the defense to prepare for the upcoming play. When a team's players are not set for that minimum duration, it constitutes a violation that results in a penalty.

The correct answer reflects this violation as a 5-yard penalty for illegal motion. This type of penalty occurs when players are moving or not properly set when the ball is snapped, which can lead to confusion and an unfair advantage. This enforcement is critical for maintaining the integrity of the game and ensuring that both teams have an equal opportunity to compete effectively.

Other options present scenarios that do not apply in this situation. A 15-yard penalty for unsportsmanlike conduct is unrelated to players not being set; such conduct carries different criteria and ramifications. No penalty being assessed or merely issuing a warning would not address the need for maintaining rules regarding player positioning before a snap, as the focus is on enforcing the requirement for players to be set for at least one second to promote orderly play.