What is the term which refers to the supply of electrical energy required to supply radio

What is the term which refers to the supply of electrical energy required to supply radio installations on every ship for the purpose of conducting distress and safety radio communications in the event of failure of the ship’s main and emergency sources of electrical power？

A.Emergency power

B.Reserve source of energy

C.Ship’s emergency diesel generator

D.Ship’s standby generator

请帮忙给出正确答案和分析，谢谢！