Which of the following is NOT a signal for a fault?

The signal pertaining to touching the shoulder with a hand is not a recognized signal for a fault in volleyball officiating. This action does not convey any specific violation or infraction during play. In contrast, the other options each serve a clear and standard purpose within the context of officiating.

For instance, raising one hand above the head is typically used to indicate a fault or violation, making it an important part of the referee's signaling system. Extending both arms sideways likewise communicates certain faults, such as a net violation. Waving one arm in a circular motion often signifies a replay or a let serve, which also connects with the officiating communication. Each of these signals has a standardized meaning to ensure clear communication of infractions to players, coaches, and spectators. Thus, the option that involves touching the shoulder does not fit into the established protocols for signaling faults in volleyball, highlighting its distinction from the other options provided.