Use the indicated entry as the pivot and perform the pivotin
     Use the indicated entry as the pivot and perform the pivoting once. [x_1 x_2 x_3 x_4 x_5 x_6 z  1 2 1 1 0 0 0 10  2 2 3 0 1 0 0 36  4 1 1 0 0 1 0 18  -2 -1 -3 0 0 0 1 0]  A. [x_1 x_2 x_3 x_4 x_5 x_6 z  3 -1 0 -1 0 0 0 4  -1 -4 0 -3 1 0 0 6  4 1 1 0 0 1 0 18  0 1 0 0 1 0 1 36]  B. [x_1 x_2 x_3 x_4 x_5 x_6 z  1 2 1 1 0 0 0 10  -5 -8 0 -3 1 0 0 6  5 -3 0 -1 0 1 0 8  -1 7 0 -3 0 0 1 30] [x_1 x_2 x_3 x_4 x_5 x_6 z 3 -1 0 -1 0 0 0 4  -10 -1 0 0 1 -3 0 18  4 1 1 0 0 1 0 18  0 1 0 0 1 0 1 36]  D. [x_1 x_2 x_3 x_4 x_5 x_6 z  1 2 1 1 0 0 0 10  -1 -4 0 -3 1 0 0 6  3 -1 0 -1 0 1 0 8  1 5 0 3 0 0 1 30] 
  
  Solution
Answer is D because we have to make key element as 1 and remaining elements in the key element column as zero

