5 points (5 points) Suppose X1, X2, . . ., Xn. ~N(u, 2). We know that X is a good estimator of u. We also know that X is unbiased, i.e., EX = p. To estimate of, we have the following two options: . $2 = 1 n - 1 ELI(X, - X) 2; 1 . $2 = - Et(X, - X) 2. n If we would like to have an unbiased estimate of o?, which estimator should we use? Justify your conclusion