Bad traveling conditions had seriously ________their progress to their destination in that region.
句意：恶劣的旅行条件严重阻碍了他们前往那个地区的目的地。tug用力拉； 竞争。demolish破坏；毁坏。hamper妨碍；束缚。destroy破坏；消灭。根据句意可知， hampered最为符合。故正确答案为C。