Final answer:
The sequence of columns in a relation can be changed without affecting the meaning or use of the relation.
Step-by-step explanation:
In a relation, the sequence of columns can be interchanged without changing the meaning or use of the relation. This is because in database terminology, a relation is essentially a table, where each column represents an attribute, each row represents a record, and the primary key is a special attribute used to uniquely identify each row.
The relation itself encompasses the set of rows and the definition of columns, but the order of those columns is not significant to how the relation is used or interpreted.
Therefore, the answer is A) Relation. Even if the sequence of columns is changed, the relation retains its structure and function, as long as the relationships between the attributes within each row are maintained.