Possible Clues:

• Courses for coll. credit
• College-level H.S. courses
• H.S. exams
• High-level H.S. classes
• Tough H.S. exams
• Some H.S. classes
• College-level HS classes
• H.S. exams for college credit
• College-level high school tests: abbr.
• Tests graded on a scale of 1 to 5: Abbr