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 = AWhich of the following sets is computed by the above query?

• A. Names of students who have got an A grade in all courses taught by Korth
• B. Names of students who have got an A grade in all courses
• C. Names of students who have got an A grade in at least one of the courses taught by Korth
• D. None of the above