Consider the following two relations for Millennium College:

STUDENT(StudentID, StudentName, CampusAddress, GPA) REGISTRATION(StudentID, CourseID, Grade)

Following is a typical query against these relations:

SELECT Student_T.StudentID, StudentName, CourseID, Grade FROM Student_T, Registration_T WHERE Student_T.StudentID = Registration_T.StudentID AND GPA > 3.0
ORDER BY StudentName;

a. On what attributes should indexes be defined to speed up this query? Give the reasons for each attribute selected. 

b. Write SQL commands to create indexes for each attribute you identified in part a.