Bottom out hint
When a tutoring system (or other software) gives help via a hint sequence, the last hint in the sequence is called a bottom out hint. It typically explains exactly what the student should do next, i.e., conveys the answer.
For example, suppose the student is trying to solve 2x=15 for x. The student doesn't know how to start, so the student clicks on the Help button. Suppose the first hint is, "You need to get x all by itself on the left side of the equation, but it is currently multiplied by 2. What can you do to undo the multiplication?" Suppose the student doesn't know what to do, so the student asks for another hint. This continues until the system finally says, "You need to divide both sides by 2, so enter '2x/2 = 15/2'." This is the bottom out hint.