Having prepared himself well for the realtor exams and having exhausted everyone in the family with his requests that someone help him with the true-and-false drills, Jeffrey, who had never been a particularly good student in high school, knew he was ready to take on the greatest challenge of his life.
选项：

A:This sentence is correct
B:drills; Jeffrey
C:Jeffrey - who had never been a particularly good student in high school - knew