A rule in a limited entry decision table is a
Answer is C : Column of the table consisting of condition entries and corresponding action entries
A decision table is an excellent tool to use in both testing and requirements management. Essentially it is a structured exercise to formulate requirements when dealing with complex business rules. Decision tables are used to model complicated logic.
Can look at it for more depth : https://en.wikipedia.org/wiki/Decision_table
Here is an example from wiki.