Which abbreviation indicates a westbound controlled signal?

The abbreviation that indicates a westbound controlled signal is WBCS. In railway terminology, the prefix "W" typically denotes "west," and "B" often stands for "controlled," while "CS" represents "signal." Therefore, WBCS succinctly communicates that it is a signal controlling westbound movements.

The other options might utilize some of the same elements but do not conform to the standard naming conventions used in the industry for controlled westbound signals. Each of the alternatives, while potentially plausible, does not align as clearly with the established meaning of signals in this context. Understanding the components of railway signal abbreviations is crucial for interpreting them accurately and ensuring safe operations.