You need to know how to recognize the limit definition of the derivative in this section. You also need to understand that the derivative at a point is the instantaneous rate of change. See below.
If you try to pass this section without understanding this equation, you are going to have a bad time and retake this many times. This particular quiz has 2 of the biggest records for number of retakes because some students have taken this quiz multiple times without learning the above equation!
Link for more: information: http://webpages.charter.net/mwhitneyshhs/calculus/deriv_at_point/deriv_at_point.html