Garden Rose -- I strongly doubt, have seen no sign, that China or Russia or India has any doubt whatsoever whether an attack would be 'realistic' -- they know our capabilities and can see as well as anyone what capabilities we have in position and ready to go
as for 'not realistic', that would cover notions such as that any or all of them would intercede or otherwise take hostile action against us if we do attack Iran -- no sign I've ever seen that they have committed or positioned any of their capabilities to defend Iran against such an attack -- a card they would have played long ago if that were the game