Where is the su log located?（）

A. su 
B. su root 
C. su - root 
D. su -c "root"

A.The error daemon runs in the foreground and reads the /etc/errpt file. 
B.The error daemon is invoked by the user when required and it reads the /usr/lib/errpt. 
C.The error daemon is invoked whenever the error occurs and it reads the /usr/lib/errpt. 
D.The error daemon /usr/lib/errdemon runs in the background on most machines and reads the /dev/error special file.

A. Messages 
B. Software 
C. Hardware 
D. Unknown