Consider the following linear regression: Yi = B1 + 32 . TREAT, + B3AFTER; + BA(TREAT, x AFTER,) + e; where Y, is an outcome for individual i. TREAT, takes value 1 if individual i is subjected to a policy change (treatment group) and zero otherwise (control group), AFTER, takes value 1 if data on individual i is collected after the policy and zero otherwise. Which interpretation is incorrect? Select one: a. B, + By + B3 = Mean for treatment group after policy change. D. B1 + By = Mean for treatment group before policy change. C. B. = Mean for control group before policy change O d. B+ + 83 = Mean for control group after policy change