What is the meaning of "Reserve Source of Energy"?

Correct Answer: Option A — The supply of electrical energy sufficient to operate the radio installations for the purpose of conducting Distress and Safety communications in the event of failure of the ship's main and emergency sources of electrical power.

Under USCG National Maritime Center examination standards, the accepted correct answer is: The supply of electrical energy sufficient to operate the radio installations for the purpose of conducting Distress and Safety communications in the event of failure of the ship's main and emergency sources of electrical power..