Mouth guards are increasingly becoming required equipment for contact sports. Besides the obvious benefit of protecting an athlete' s teeth, mouth guards also prevent concussions. Youth league referees should penalize teams with players participating without a sanctioned mouth guard. Which of the following most accurately expresses the argument's main conclusion? ['It is generally preferable to wear mouth guards while playing contact sports.', 'Mouth guards protect teeth and prevent concussions.', 'Mouth guards should always be worn during contact sports.', 'Mouth guards save lives.']