49. 依據SOLAS Chapter 11-2, Regulation 62，油輪的inert gas system至少要設置有兩種防止油艙氣體回流至機艙鍋爐的裝備，下列哪項是強制需要的裝備？ (A)甲板水封 Deck Water Seal (B)洩壓閥Exhaust valve (C)壓力調節閥IG Pressure regulating valve (D)甲板隔離閥Isolating valve