Question 4 (1 point) Consider the following Scala case class and function definitions: trait Result[+X,+Y] case class Error[+Y] (s:Y) extends Result[Nothing, Y] case class Ok [+X] (n:X) extends Result[X, Nothing] def combine[U, X,Y] (us:List[U], f:U=>Result[X, Y]) : Result[List[X],List[Y]] = { us match { case Nil => Ok (Nil) case v::vs => (f (v), combine (vs, f)) match { case (Error (s), Error (ss)) => Error (s::ss) case (Ok (n), Error (ss)) => Error (ss) case (Error (s), Ok (ns)) => Error (List (s)) case (Ok (n), Ok (ns)) => Ok (n::ns) } } } What is the output of running: combine (List(1,2,3), (n:Int) => if (n%2==0) Ok (n) else Error (n))