When can substitutions occur in a high school volleyball match?

Substitutions in high school volleyball are allowed between rallies and during stoppages in play, making this the correct and most accurate choice. This rule is designed to maintain the flow of the game while allowing coaches to manage their players effectively. Substitutions can occur after a rally has concluded, which ensures that both teams are ready for the next play, thus preventing disruptions during the actual play. This timing provides opportunities for strategic adjustments as the match progresses.

In contrast, other situations, such as a serve or timeouts, do not typically allow for substitutions. Allowing substitutions during a serve would create interruptions and potentially confuse players during critical moments. Additionally, restricting substitutions to only timeouts would limit a coach's ability to react to ongoing developments in the match. These constraints highlight the importance of allowing flexibility to make changes between rallies and during stoppages, ensuring a smooth and efficient game experience.