Let us consider the $2$ automata A and $B$ given Figure $1.$

$($a$)$ Build the parallel product.

$($b$)$ Build the synchronised product if Sync $=\{(a,b),(b,b),(c,lon)\}.$

$($c$)$ Build the synchronous product if Sync $=\{(a,b),(a,c)\}.$

Figure $1$: $2$ automata A and $B$