In volleyball, what is the role of the libero?

The role of the libero in volleyball is that of a defensive specialist, and this is supported by specific uniform requirements that distinguish the libero from other players on the team. The libero wears a different color jersey, making it easy for officials, players, and spectators to identify them. This player is allowed to replace any back-row player without prior notice to the officials, helping to increase the team's defensive capabilities. The libero cannot attack the ball above the net's height and has limitations on serving, as they typically do not serve continuously throughout the match.

In contrast, the other options do not accurately describe the libero's role. The libero is not an offensive player with specific serving rules, nor do they serve when requested by the coach or substitute without restrictions. Understanding the distinct functions and regulations concerning the libero is crucial for both players and officials in the sport of volleyball.