Under what condition can a signal be displayed into an OOS track?

The correct choice is based on the strict protocols surrounding the operation of trains in out-of-service (OOS) tracks. The requirement that the limits of the OOS are verified through Form D ensures that all personnel involved are aware of the specific areas where track work or maintenance is being performed, thus providing safety and preventing accidents. The verification process through Form D includes details about the limits of the OOS track and any restrictions that may apply, which is crucial for maintaining clarity and preventing unauthorized access or train movements in areas that are not deemed safe for operation.

Operating a train on an OOS track without proper verification could lead to serious safety hazards, hence the emphasis on having formal documentation and clearance before a signal can be displayed for that track. Other options do not provide the necessary verification or compliance with safety regulations associated with operating in an OOS setting.