C. Credit for an exam typically equals what students enrolled in the course would earn.
CLEP stands for College Level Examination Program. Which is a series of tests in different subject areas to determine if the person being examined has the equivalent knowledge of the subject that a typical student in college would gain after taking a class in that subject. CLEP is quite useful for advanced students to skip pass introductory classes. By taking a CLEP and passing the CLEP, a student will generally save quite a bit of money since tuition for the actual class doesn't need to be spent and will save the time that the student would have had to spend taking the class. With that in mind, let's look at the options and see what does and does not make sense.
A. Students who fail a course can take a CLEP exam to earn credit for that course.
* This is actually true, but to honest, it's highly unlikely that a student who failed the course would actually pass the CLEP. So this is a bad choice.
B. Students aren't given credit for an exam unless they earn a perfect score.
* Nobody's perfect and the CLEP doesn't expect you to be perfect. Just be good enough. Just like college doesn't require a 4.0 GPA, CLEP doesn't require a perfect score. So this is a bad choice.
C. Credit for an exam typically equals what students enrolled in the course would earn.
* This is exactly correct. One of the major reasons for taking a CLEP is to bypass introductory classes to various subjects. The $85 for the CLEP exam is a lot cheaper and faster than the close to $1000 average for a college class. This is the correct choice.
D. Students enrolled in a course can take a CLEP exam instead of the final to earn credit for the course.
* You could do this, but it's rather silly since the CLEP is very much like the final exam in a college class. And since you've spent the time in class, why spend an extra $85 to effectively take the same type of exam? So this is a bad choice.