During the course of a voyage，a seaman falls on the main deck and injures his ankle. The Master should submit a Report of Marine Accident，Injury or Death if the（）.

A.injured is unfit for duty

B.injured is able to return to work

C.injury results in loss of life only

D.injury is the result of misconduct

随机干扰往往是以瞬变、尖峰或脉冲形式出现，它是由（）造成的。

A.温度变化

B.电压效应

C.电动工具的火花

D.电感性负载的启停

E.光电效应