${\mathbf{B}}=\left[\begin{array}{lll}5 & 0 & 0 \\0 & 3 & 0 \\0 & 0 & 2\end{array}\right]$ হলে $B^{-1}=$ কত?

$\frac{1}{30}\left[\begin{array}{lll}5 & 0 & 0 \\0 & 3 & 0 \\0 & 0 & 2\end{array}\right]$

$\frac{1}{30}\left[\begin{array}{lll}\frac{1}{5} & 0 & 0 \\0 & \frac{1}{3} & 0 \\0 & 0 & \frac{1}{2}\end{array}\right]$

$\left[\begin{array}{ccc}\frac{1}{5} & 0 & 0 \\0 & \frac{1}{3} & 0 \\0 & 0 & \frac{1}{2}\end{array}\right]$

$\left[\begin{array}{lll}\frac{1}{2} & 0 & 0 \\0 & \frac{1}{3} & 0 \\0 & 0 & \frac{1}{5}\end{array}\right]$