"he had been splashing in the shallow end until the shrill sound of the lifeguard's whistle cut through the air like a siren,"
in this sentence, the whistle most likely symbolizes
danger
embarrassment
power
temptation

In the given sentence above, the word "whistle" most likely symbolizes power. The correct answer would be the third option. The "whistle" serves as the symbol of power in this sentence because it was like a savior of the person who had been splashing in the shallow end. In addition, it was also like a siren. A siren is a device with a loud, prolonged sound which usually signals a warning making anyone who hears this, pays attention to it.