5. Let X be the number of the MAT 301 students who show up at Professor Song's office hours on a particular day. Suppose that the only possible values of X are 0, 1, 2, and 3, and that p(0) = p(1) = p(2) = p(3) = 0.25. a. What is the moment generating function(mgf) of X? b. Calculate E(X2) by using the mgf