You wish to kill a process with a PID of 123. Select the command which exiting.（）

A. tr ’\r\n’ " < userlist.txt > newlist.txt
B. tr -c ’\n\r’ " < newlist.txt > userlist.txt
C. tr -d \r¯ < userlist.txt > newlist.txt
D. tr \r¯\n¯ userlist.txt newlist.txt
E. tr -s ®^M’¡®^J’ userlist.txt newlist.tx

A. foo and bar would both be removed.
B. foo would be removed while bar would remain accessible.
C. foo would be removed， bar would still exist but would be unusable.
D. Both foo and bar would remain accessible.
E. You would be asked whether bar should be removed.