When the derailing switch is open, trap indicator shows red target by day and ________ Light by night. A. Red B. Green C. Yellow D. White

The correct answer is red light.

A derailing switch is a type of switch that is used to divert a train from its normal track onto a side track. The trap indicator is a device that is used to show the train driver whether the derailing switch is open or closed. When the derailing switch is open, the trap indicator shows a red target by day and a red light by night. This is to warn the train driver that the track is not safe to travel on.

The other options are incorrect because they are not the colors that are shown by the trap indicator when the derailing switch is open.