Question 2 : Plot the 2-D Gaussian as well as the contour map (i.e., projection of this Gaussian on the x-y plane) with the following covariance characteristics. From the plots, elaborate on the physical meaning of each element in the covariance matrix (you should learn at least 3 things if given an arbitrary covariance matrix). This is not based on the given dataset. (Note: Suggest to generate a 4x2 plot with the left column the 2-D Gaussian and the right column the contour plot.) a) The off-diagonal elements are zero and the diagonal elements are equal to each other b) The off-diagonal elements are zero and the diagonal elements are not equal to each other c) The off-diagonal elements are positive and the diagonal elements are not equal to each other d) The off-diagonal elements are negative and the diagonal elements are not equal to each other