The main purpose of setting the screen doors is to safeguard the safety of passengers, reduce energy consumption and the noise of train operation and eliminate the impact of _______________ on passengers. 设置屏蔽门的主要目的是为了保障乘客的安全，降低能耗和列车运行的噪音，消除_______________对乘客的影响。
A、unsteadiness 不平稳
B、tunnel piston wind隧道活塞风
C、vibration 震动