Fill in the information in the following proof for this argument

$(WG)$

$(AP)$

$(WvvA)$

$I(PvvG)$

$|P|$ from $4$ by NOR

$1A$ from

$1W$ from

$IG$ from $1,7$ by IF THEN

I $G$ from $4$ by NOR

$10./G$ from $9$ by NN

:$.(PvvG)$ from $4-9$ by RA

What is the missing justification for line $6?$

from $2,5$ by IF THEN

from $1,5$ by NOR

from $5$ by NN

from $4,5$ by IF THEN