The correct answer is A. TA-912.
TA-912 is the authority to proceed that will be served to the loco pilot from the opposite direction in an automatic section with temporary single line working on a double line section. It is a train order that authorizes the train to proceed on the single line section. The train order must be signed by the authorized railway employee and must be carried by the train crew.
The other options are incorrect because they are not the authority to proceed that will be served to the loco pilot from the opposite direction in an automatic section with temporary single line working on a double line section.
B. TB-912 is a train order that authorizes the train to proceed on a double line section.
C. TD-912 is a train order that authorizes the train to proceed on a single line section.
D. TC-1425 is a train order that authorizes the train to proceed on a section with temporary single line working.