Let $A=\begin{pmatrix} 1 & 1 & 0\\ 0 & a & b\\1 & 0 & 1 \end{pmatrix}$. Then $A^{-1}$ does not exist if $(a,b)$ is equal to
A matrix is not invertible if it's determinant is $0.$
$|A|= 1(a-0)-1(0-b)= a+b$
Only Option A) satisfies
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