The correct answer is: A. T/369(1).
A colour light distant signal is a type of railway signal that uses a combination of red, green, and yellow lights to indicate the status of the track ahead. A blank-off signal is a signal that is not displaying any lights. When a colour light distant signal is blank-off, it means that the signalman at the next station has not received a train order from the signalman at the station in rear. This means that the train is not authorized to proceed past the signal.
In order to proceed past a blank-off signal, the train must receive authority from the station in rear. This authority is given in the form of a train order, which is a document that authorizes the train to proceed past the signal. The train order must be signed by the signalman at the station in rear.
Option A, T/369(1), is the correct answer because it is the only option that states that the train must receive authority from the station in rear before proceeding past a blank-off signal. Options B, T/409, and C, T/A409, are incorrect because they do not state that the train must receive authority from the station in rear. Option D, No Need of any Authority, is incorrect because it is not true that the train does not need authority from the station in rear to proceed past a blank-off signal.