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Problem 2 (25 points) For this problem do not justify any answers. Just pick the right answer to each question. a. Consider a regression with two variables, in which X, is the variable of interest and X2, is the control variable (it may still be correlated with the error term). Then the OLS assumption 1 requires that: A) E(u;(X X21) = 0 B) E(u,(X,) = 0 CTE (uilX,i, X2i) = E(uilX,) D) E(uilX,i, X2) = E(uilX21)