The screen door system is the fully enclosed and tightly sealed ______________________, offering the platform with safety, economy, resource-saving and silence, as well as more efficient and effective operation. 屏蔽门系统为全封闭密闭______________________，提供安全、经济、节约资源、静音的站台，保障运行更高效、有效。
A、station building 车站大楼
B、automatic gate machine自动闸机
C、platform safety gate system 站台安全门系统