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

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