Final answer:
The word 'spectator' refers to 'B. one who watches' at a sports event, based on its Latin root 'spec', which means 'to look or see'.
Step-by-step explanation:
Based on the Latin root spec, which means "to look or see," the best meaning for the underlined word spectator in the paragraph would be B. one who watches. A spectator at a sports event is someone who is in the stands to observe the game, cheering and providing encouragement to the athletes. This person does not participate in the game directly but is an essential part of the event by watching and reacting to the play. The action of the spectator in the provided paragraph confirms this as they reached out to catch the ball, which is an interaction spectators have with the game, even though they are not catching as part of the gameplay.