Suppose that there is a running variable (such as GPA) that have a sharp cutoff (such as 3.8). If a student has a GPA above the cutoff, they are eligible to receive a very generous scholarship to attend college. You are interested in studying the effects of attending college on risky health behaviors. Given this description, which of the following is the most appropriate technique for your study?

a)difference-in-difference (DiD)

b)instrumental variables (IV) c)regression discontinuity design (RDD)