$M$ is a square matrix of order $’n’$ and its determinant value is $5.$ If all the elements of $M$ are multiple by $2,$ its determinant value becomes $40.$ The value of $’n’$ is
$\left | k\times A_{n\times n} \right |=k^{n}\times\left | A_{n\times n} \right |$ (Reference: Determinant when multiplying a matrix by a constant)
$\therefore$ Let the original value of determinant be $\Delta$ i.e. $\Delta=5$
When each element of the matrix is multiplied by $2$, the resultant determinant becomes $40$
$\therefore$ $2^{n}\times 5=40 \Rightarrow 2^{n}=8 \Rightarrow n=3$
Option B is correct.
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