Track and time authority limits designated by a switch extend only to where?

The correct answer pertains to the specific operational limits of track and time authority as it relates to switch control. Track and time authority is granted for movements on a track segment, and it is crucial for ensuring safe operations. When a switch is involved, the authority established is directly tied to the signal that governs movement over that switch.

This means that the authority extends only as far as the point where the signal provides the necessary indication for movement. The reason this is the correct answer is that signals are designed to communicate specific, actionable information about the state of track ahead, including the status of switches. By limiting the authority to the controlling signal, it ensures that the movement is safe and aligns with operational protocols.

The other options describe broader locations or segments of track but do not specifically address the unique nature of authority that applies to switches and the immediate signals governing them. Therefore, B accurately captures the relationship between the track, switch, and the governing signal in the context of track and time authority.