Answer:
B. Cardinality
Explanation:
If your university has a policy that states you must take a minimum of 12 hours to be considered a full-time student and take no more than 21 hours without special permission, the 21 hours rule is referred to as cardinality.
Cardinality establishes a relationship between two extremes, it is used to set a limit on two extremes of an entity, it is the number of entities in a set.
