What does a guard's whistle indicate?

A lifeguard’s whistle serves primarily as a warning or notification for patrons to pay attention. When a lifeguard blows their whistle, it typically signals that there is an important situation occurring that requires the attention of all swimmers in the area. This could relate to various circumstances such as advising swimmers to adhere to pool rules, alerting them to potential dangers, or indicating a need to clear the pool for safety reasons.

This action helps maintain order and enhances safety by ensuring that swimmers are aware of their surroundings and can respond appropriately if necessary. The sound of the whistle cuts through the noise of recreational swimming, making sure that patrons understand there is an immediate announcement or action they need to be aware of.

While the other options present plausible scenarios that involve a whistle, they are not aligned with the primary function of a lifeguard's whistle. For instance, the start of a swim race typically involves a starting gun rather than a whistle. Similarly, leaving the pool or gathering for a meeting generally do not necessitate the use of a whistle, and instead would rely on verbal communication or signals explicitly associated with those situations. Therefore, the correct answer emphasizes the critical role a whistle plays in promoting awareness and safety in aquatic environments.