Translation:Four Russian girls are looking for a dog, which is well behaved but intelligent.
I don't know about that. Minulla on hevonen joka kiltti mutta älykäs, and he can be a pain in the butt. (In truth, that should be past tense: I used to have a well-behaved but intelligent horse; he's in that Greenest Pasture, now.) For all that he was well-behaved, his intelligence got him into trouble more than you might imagine, including a time or two where I had to go searching for him. Using mutta would be entirely appropriate. I still miss him...
Okay... "Four Russian girls are looking for the dog, who is well-behaved but intelligent" was counted incorrect. I know they were looking for "which" instead of "who" since we are not talking about a human, but is my definite article also incorrect? Or could either definite or indefinite be correct here?