Perform the Sequence of Row Operations on the Matrix $$\left[ \begin{array} { c c c } 1 & 1 & - 7 \\4 & 5 & - 7 \\1 & 3 & 35\end{array} \right]$$

Multiple Choice

Perform the sequence of row operations on the matrix.What did the operations accomplish?​ $$\left[ \begin{array} { c c c } 1 & 1 & - 7 \\4 & 5 & - 7 \\1 & 3 & 35\end{array} \right]$$ ​ Add -4 times R₁ to R₂,
Add -1 times R₁ to R₃,
Add -2 times R₂ to R₃,
Add -1 times R₂ to R₁.
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A) $$\left[ \begin{array} { l l l } 1 & 0 & 0 \\0 & 1 & 0 \\0 & 0 & 1\end{array} \right]$$ The operations produce a row-equivalent matrix in reduced row-echelon form.
B) $$\left[ \begin{array} { r r r } 1 & 0 & - 28 \\0 & 1 & 21 \\0 & 0 & 0\end{array} \right]$$ The operations produce a row-equivalent matrix in reduced row-echelon form.
C) $$\left[ \begin{array} { r r r } 1 & 1 & - 28 \\0 & 1 & 21 \\0 & 0 & 0\end{array} \right]$$ The operations produce a row-equivalent matrix in reduced row-echelon form.
D) $$\left[ \begin{array} { c c c } 1 & 1 & - 7 \\0 & 1 & 21 \\0 & 2 & 42\end{array} \right]$$ The operations produce a row-equivalent matrix in reduced row-echelon form.
E) $$\left[ \begin{array} { r r r } 1 & 0 & - 28 \\0 & 0 & 21 \\0 & 0 & 0\end{array} \right]$$ The operations produce a row-equivalent matrix in reduced row-echelon form.