A student knows that they need guidance above what they are getting from their teacher. They approach a person to tutor/mentor them, and the person agrees. The mentor knows what is required to excel in the course of study.

The student listens carefully to the mentor, and after a period of time, the mentor tell the student that they have learned all that they need.

The student takes the test, and accurately follows everything he learned from the mentor.

Later the student is shocked to learn that they got a mediocre or poor grade, and returns to the mentor...
a) The mentor must admit that he failed the student?

or

b) The mentor chastizes the student for not asking the "right" questions.