21 (2 points) Given the course database above, which of the following queries in SQL represents the following English query: What are the last names of all of the students? SELECT * FROM students SELECT student, class WHERE classes.student_id = (student_id); SELECT last name FROM students; SELECT students FROM last name; SELECT last_name FROM students WHERE (last_name} Course database: STUDENTS (STUDENT_ID, LAST_NAME, FIRST_NAME) COURSES (COURSE_NUMBER, COURSE_NAME) CLASSES (STUDENT_ID, COURSE NUMBER, SECTION)