The number of attributes in relation is called as its

Concept

In the relational model, two distinct properties describe the size of a relation (table). The degree is the number of attributes (columns) in the relation, also known as its arity. The cardinality is the number of tuples (rows) in the relation. These count different things: degree counts columns, cardinality counts rows.

Application

The question asks for the term that counts the number of attributes (columns) in a relation. By definition, the count of attributes is the degree. So the value that completes the sentence is Degree.

Contrast

• Cardinality counts tuples (rows), not attributes, so it answers a different question.

• Tuples are the rows themselves; a row is an instance of data, not a count of columns.

• Entity is an ER-model concept (a real-world object that becomes a table); it is not a count of attributes.