Given the following relational database schema:

Student = (SSN, Name, Major)

Course = ( CourseNumber, PrerequisiteCourseNumber, Course Title, NumberUnits)

Section = ( CourseNumber, Quarter, RoomNumber, DayTime), where DayTime is of the form MW 1:0-2:00PM.

Enrollment = (SSN,CourseNumber, Quarter, Grade)// Grade is either Null or a letter grade.

Express the following queries using appropriate SQL statements with a minimum number of operations:

a)List every CoursaeNumber and Quarter which has the highest enrollment.

b)List every CourseNumber and CourseTitle which has the highest enrollment based on all quarters.

c)List the name and major of every student who has completed the highest number of units.