Which of these is the best description of what a reference table contains?

Data that frequently change, such as the shipping statuses of active orders

Key$-$value pairs where the first column is the primary key and the other column$($s$)$ contain the value$($s$)$

Data that serve as a bridge between two entities that have a many$-$to$-$many relationship between them

A list of all the relationships in the database and their cardinality