The correct answer is: Block Section.
A block section is a section of track that is controlled by a single signal. The BSLB determines the limits of the block section and the location of the signals.
A station section is a section of track that is located between two stations. The station section is not controlled by a single signal, but by a series of signals that are located at the entrance and exit of the station.
A station limit is the point at which a train must stop before entering a station. The station limit is determined by the BSLB and is located at the entrance to the station.
None of these is the correct answer because it does not accurately describe the function of the BSLB.