SQL

Consider the set of relations shown below and the SQL query that follows.

  Students: (Roll_number, Name, Date_of_birth)
  Courses: (Course number, Course_name, Instructor)
  Grades: (Roll_number, Course_number, Grade)
  select distinct Name
  from Students, Courses, Grades
  where Students. Roll_number = Grades.Roll_number
      and Courses.Instructor = Korth
      and Courses.Course_number = Grades.Course_number
      and Grades.grade = A 

Which of the following sets is computed by the above query?