Use these matrix as a key for Hill's cipher

a$)$ To encrypt the message "STOP MOVE"

$A=\left[\begin{array}{c}23\\ 58\end{array}\right],B=\left[\begin{array}{cc}3& 5\\ 5& 8\end{array}\right],C=\left[\begin{array}{c}37\\ 25\end{array}\right]$

b$)$ To decrypt the message with them. $(A-z$:$0-25)$