Figure 2-27 represents a situation of students who attend and work in schools and who also belong to certain clubs that are located in different schools. Study this diagram carefully to try to discern what business rules are represented.

a. You will notice that cardinalities are not included on the Works For relationship. State a business rule for this relationship, and then represent this rule with the cardinalities that match your rule.
b. State a business rule that would make the Located In relationship redundant (i.e., where the school in which a club is located can be surmised or derived in some way from other relationships).
c. Suppose a student could work for only a school the student attends but might not work. Would the Works For relationship still be necessary, or could you represent whether a student works for the school she attends in some other way (if so, how)?
d. Based on the rules of the ERD in Figure 2-27, is it possible for a student to belong to a club located in a school that the student does not attend? Explain.