Give the Matlab command to create the following matrix as $M$ in the workspace

$\backslash$table$[[1,2,3],[4,5,6],[7,8,9]]$

a$.$ Use the sum command to sum the third column of the matrix. Use the: operator to indicate all rows.

$M=[1,2,3$;$4,5,6$;$7,8,9]$

${\displaystyle \underset{?}{\overset{?}{}}}(M($:$3))$

b$.$ Give the command that will find the product of $M_{22}$ and $M_{31}$