Explanation: "Marking a starting point and setting a timer" is the first step to check the reading rate of a student because this step defines the time the student will be evaluated. The second step is "reading aloud with a timer".
B is the most reasonable answer, because the first step is marking a starting point and setting a timer; the second one should go next because you can´t count the number of words read if you haven´t read them yet.
