What does this boundary parser print?

What does this boundary parser print?

def parse(raw: String): Either[String, Int] =
  raw.trim.toIntOption
    .filter(1 to 5 contains _)
    .toRight("invalid")

@main def run(): Unit =
  println(List(" 3 ", "0", "many").map(parse))

1. List(Right(3), Left(invalid), Left(invalid))
2. List(Right(3), Right(0), Left(invalid))
3. The program throws NumberFormatException on "many".
4. The program does not compile because toIntOption is nullable.