How many digits can a player's number be, including the libero?

A player's number in volleyball, including that of the libero, can consist of two digits, ranging from 00 to 99. This is in accordance with the regulations set by governing bodies like the FIVB and NCAA, which establish the format for player numbering.

Player numbers must be distinct and easy to identify, and having a two-digit numbering system allows for a sufficient range of numbers to accommodate a larger roster without causing confusion on the court. This system also helps in maintaining clarity for officials, players, and spectators.

In contrast, options suggesting one digit, three digits, or four digits extend beyond this established framework, making them incompatible with current volleyball rules for player identification.