Which of the following is the command to find 30 days old files in the location /app/unix if you are currently at location /tmp/user?
find /app/unix -mtime +30 -exec ls -lrt {} \ /tmp/user;
find /app/unix -mmonth +1 -exec ls -lrt {} \;
find /app/unix -mday +30 -exec ls -lrt {} \;
find /app/unix -mtime +30 -exec ls -lrt {} \;