9. 某船依航向155°航行116浬,然後轉向217°航行104浬,最後轉向345°航行138浬。請以聯向航法(Traverse Sailing)推求該船之實際航向(C.M.G.)為何? (A) 318.1° (B) 311.9° (C) 228.1° (D) 221.9°