1. Which of the following 3x3 matrices are in reduced row-echelon form? (a) [100] 010 001 2. (c) 0 1 0 001 000 (e) 100 000 001 (2) 110 010 000 [001] 000 [000] (a) [100] 010 001 (c) 100 010 020 15 01 (b) [100] 010 0 0 (d) 100 001 000 (f) 000 (h) 0 1 07 100 000 O Which of the following 3x3 matrices are in row-echelon form? (b) [120] 010 000 013 000 00 230 000 000 (d) 1 3 4 001 000 (f) 123 000 001