The emergency source of power for Mobile Offshore Drilling Units should be capable， having regard to starting currents and the transitory nature of certain loads， of supplying simultaneously at least the services specified in 5.3.6 of the 1989 MODU Code. Which one of the following service is not required to be supplied from the emergency power for a period of 18 hours？（）

A.Emergency lighting at every embarkation station on deck and over sides
B.Emergency lighting at the storage positions for firemen’s outfits
C.Fire and gas detection and their alarm system
D.Power to operate the watertight doors and their indicators