Which statement is TRUE concerning spare charges for portable fire extinguishers on unmanned tank barges?

A
Spare charges shall be carried for at least 50 percent of each size and variety required on board.
B
If the unit cannot be charged by the vessel's personnel, one spare unit shall be carried in lieu of spare charges.
C
Spare charges shall be stowed in watertight containers on deck.
D
Regulations concerning spare charges do not apply to unmanned barges.
E