Which of the following is NOT one of the three official hand movements for flagging?

The correct choice is D, which refers to "Begin." In flagging practices, there are three official hand movements that are universally recognized for directing traffic: Stop, Proceed, and Alert/Slow. These movements are critical for ensuring clear communication between the flagger and drivers, enhancing safety on work sites or in areas of traffic control.

"Stop" is represented by the flag held in an upright position, signaling vehicles to halt. "Proceed" involves signaling with the flag in a horizontal position, indicating that it is safe for vehicles to continue. "Alert/Slow" is typically represented by holding the flag at an angle, notifying approaching vehicles to reduce speed and be cautious.

Since "Begin" is not an official hand movement in this context, it does not belong to the standard set of signals used by flaggers. Recognizing these movements is essential for effective flagging practices and maintaining safety in areas where traffic control is necessary.