成语“爱屋及乌”中的第二个“乌”指的是什么？

AIS cannot be used to make passing arrangements because the system is not capable of this type of ship-to-ship communications
B. AIS cannot be used to make passing arrangements because the ship-to-ship text messaging feature is for emergency use only
C. AIS can be used to make passing arrangements via ship-to-ship text messaging but a vessel operator is not relieved from the requirement to sound whistle signals or make arrangements via bridge-to-bridge radiotelephone
D. AIS can be used to make passing arrangements via ship-to-ship text massaging thus relieving a vessel operator from making such arrangements via bridge-to-bridge radiotelephone or signaling intent to pass via whistle signal

A. 电压传感器
B. 甲烷传感器
C. 电流传感器
D. 馈电传感器

A. 正确
B. 错误