A junk dealer who was engged in the buying and selling of used up bottles and scrapped materials in Pangasinan uses two tracks to bring the scrapped metals to Manila for resale and back haul various cargoes from different merchants from the same place. In November 1970, he contracted with AB to have 750 cartons of milk delivered from Manila to Urdaneta. However, only 150 boxes were delivered since one of the trucks was hijacked during its trip by armed men. AB demanded from the junk dealer the lost merchandise and cargo. Is the junk dealer a common carrier so as to be bound to exercise extraordinary diligence in the vigilance over the goods? Can he not use the fortuitous event as a defense in order to be absolved from liability? Yes or no and kindly justify your answer.