Jeff Picks Up a Piece of Metal Pipe and Swings

Jeff picks up a piece of metal pipe and swings it around,hitting Gary across the back of the head.What factor would be required for Jeff's employer to be liable to Gary?

A) Jeff was at the factory when it happened.
B) Jeff voluntarily hit Gary.
C) Jeff was moving the pipe as part of his work responsibilities when he hit Gary.
D) Gary cannot be an employee of the same company as Jeff.