$(12)$ The following VHDL code checks that the number of $1$s in a $16-$bit vector v is divisible by $3$ and sets the variable div$\_$by$\_3$ to true if it is$.$ What is the if condition at XXX$?$ div$\_$by$\_3$ :$=$ false; d :$=0$; for k in $0$ to $15$ loop if v$($k$)=1$ then if d $=2$ then d :$=0$; else d :$=$ d $+1$; end if; end if; end loop; if XXX then div$\_$by$\_3$ :$=$ true; end if