Write a MATLAB routine A = ChowLiu(X) where X is a D × N data matrix containing a multivariate datapoint on each column that returns a Chow-Liu maximum likelihood tree for X. The tree structure is to be returned in the sparse matrix A. You may find the routine spantree.m useful. The file ChowLiuData.mat contains a data matrix for 10 variables. Use your routine to find the maximum likelihood Chow Liu tree, and draw a picture of the resulting DAG with edges oriented away from variable 1.