What type of light is used for night flagging signals?

The correct choice indicates that a white light with 5 fusees is used for night flagging signals. This is based on standard practices for night flagging in rail operations, where visibility is crucial for safety and clear communication of signals.

Using a white light ensures that the signal is distinct and easily recognizable in dark conditions, minimizing the risk of accidents. The number of fusees, in this case, five, contributes to the brightness of the signal, making it effective for alerting train operators and enhancing visibility from a distance.

In contrast, the other options do not conform to established standards for night flagging signals. Red lights and different colors or quantities of fusees may indicate other signals or warnings but are not designated for night flagging. Thus, the use of a white light with 5 fusees is specifically intended to provide the best visibility and clarity for safety during night operations on the railroad.