Determine Whether the Matrix Is in Echelon Form, Reduced Echelon $$\left[ \begin{array} { r r r r } 1 & 2 & 5 & - 7 \\0 & 1 & - 4 & 9 \\0 & 0 & 1 & 2\end{array} \right]$$

Multiple Choice

Determine whether the matrix is in echelon form, reduced echelon form, or neither.
- $$\left[ \begin{array} { r r r r } 1 & 2 & 5 & - 7 \\0 & 1 & - 4 & 9 \\0 & 0 & 1 & 2\end{array} \right]$$

A) Reduced echelon form
B) Echelon form
C) Neither