The interface is up and protocol is up. What level of logging is enabled when you get these messages?()<br /> <img src="https://nimg.ppkao.com/2018-07/tangxueping/2018072413453530905.jpg?sign=b16a11383b666b46d9c3631f6b03dfa3&t=62d343fe" />
A、alerts
B、errors
C、critical
D、notifications