(3) Start with a 4 by 4 matrix A whose entries are integers in the range from 1 to 10 (output A). Add a row on the bottom of A that consists of the mean of each column of A and assign the resulting matrix to B (output B). Next, add a row to the bottom of A that consists of the sums of the entries down each column of A and assign the resulting matrix to C (output C). Last, add a column to the right of A that consists of the sums of the entries across each row of A and assign the resulting matrix to D (output D). Hint: you can use MATLAB functions randi, mean, sum