Which of the following defines a firearm's action? a, it is a tube made of steel that the bullet or shot travels through it is a tube made of steel that the bullet or shot travels through b, it supports the stock and the barrel and can be made of one of two separate pieces it supports the stock and the barrel and can be made of one of two separate pieces c, it contains the parts that load, fire and eject a cartridge or shot shell it contains the parts that load, fire and eject a cartridge or shot shell d, it is the number which is located on the side of the firearm that is used for identification it is the number which is located on the side of the firearm that is used for identification