I forgot to update this yesterday but here is the final answer (thanks Irin Thirdwater!): 

`=(if(K3=if(F3=G3,1,if(F3=H3,2,if(F3=I3,3,10))),"ok","WRONG"))="ok"`

`=(if(K3=if(F3=G3,1,if(F3=H3,2,if(F3=I3,3,10))),"ok","WRONG"))="WRONG"`

The first line with green highlight, second with red.

Hope this helps in case anyone else needs it!