6. Consider a database used to record the marks that students get in different exams of different course offerings (sections). a. Construct an E-R diagram that models exams as entities, and uses a ternary relationshi, for the database. Construct an alternative E-R diagram that uses only a binary relationship between student and section. Make sure that only one relationship exists between a particular student and section pair, yet you can represent the marks that a student gets in. different exams. b