What indicates that time has expired at the end of a quarter or extra period?

The answer is correct because the rules of basketball specify that time expiration is indicated by a red light or an LED light on each backboard. This visual cue ensures that all players, officials, and spectators are aware that the period has concluded. The use of lights provides a clear and consistent signal that is universally recognized in official game play.

While a horn sound from the scoreboard might be associated with the end of periods, it is not the primary indicator as per the official rules. Similarly, a visual signal from the referee could vary in form and might not always be present, especially in the case of certain game situations. Players raising their hands does not officially signal time expiration and may simply be a response to the end of a play or a signal from a player rather than an official indication of the end of the game period. The reliance on standardized signals like the LED lights helps maintain clarity and fairness in the game.