What are the first names of all students who got a grade C in a class?
SELECT DISTINCT stu_fname FROM student AS T1 JOIN enroll AS T2 ON T1.stu_num  =  T2.stu_num WHERE enroll_grade  =  'C'
SELECT DISTINCT stu_fname FROM student AS T1 JOIN enroll AS T2 ON T1.stu_num  =  T2.stu_num WHERE enroll_grade  =  'C'
[{'STU_FNAME': 'William'}, {'STU_FNAME': 'Anne'}]