Descriptive attribute describes a relationship. It gives additional information about the relationship.For instance consider the above ER diagrams
In the first instance of ER diagram “time” is the descriptive attribute because it describes the reads relationship. It gives additional information such as “at what time a student reads a book.” In shoft, time attribute qualifies reads relationship.
Similarly in second instance, duration is the descriptive attribute. it gives additional information such as “how many hours an employee works_for a firm”.
(B)