Q$\mathrm{.}2$: Which instruction is allowed or not allowed? And why is not allowed if there is$?($Assume all numbers are in hex.$)$:

$1-$MOV AX$,27.2-$MOV DS$,$ BX$.3-$MOV DX$,23$BA$8.4-$ MOV CX$,$ CS$.$

$5-$MOV CS$,$ BH$.6-$MOV SI$,6619.7-$MOV CH$,$ AX$.8-$MOV ES$,9$BFF$.$

$9-$ MOV AL$,89$A$.10-$ MOV CX$,379.$