In the Pseudo$-$Random Generation Algorithm $($PRGA$)$ part of RC$4,$ what is the missing statement?

$i$:$=0$

$j$:$=0$

while GeneratingOutput:

$i$:$=(i+1)\%256$

$j$:$=(j+S[i])\%256.$

$$

$K$:$=S[(S[i]+S[j])\%256]$

output $K$

end while

swap values of $S[i]$ and $S[j]$

key$[$i$\%$ key$\_$length$])\%256$

$$ nothing