We can't know whether people rationally or irrationally exhibit the local bias because... Select one: O a. There is no study analyzing whether people's investments in local stocks have superior performance O b. Due to the joint-hypothesis problem, we can't know with certainty whether people's investments in local stocks have superior performance. c. The local bias has only been shown to exist for individual (not professional) investors. d. The local bias has been shown to exist both for individuals and for professional investors