In volleyball, a single player can hit the ball consecutively a maximum of 3 times before it must go over the net. However, those hits can occur in different actions during a single sequence of play (e.g., a pass, a set, and a hit). Therefore, the correct answer based on typical play rules is b. 3.
It should be noted that if a player hits the ball more than three times, it results in a fault, and the opposing team gains the point.