Which of the following commands will he use to accomplish the task?

Jain works as a contract Ethical Hacker. He has recently got a project to do security checking for www.abc.com. He wants to find out the operating system of the ABC server in the information gathering step.

Which of the following commands will he use to accomplish the task? Each correct answer represents a complete solution. (Choose two.)
A . nc -v -n 208.100.2.25 80
B . nmap -v -O www.abc.com
C . nmap -v -O 208.100.2.25
D . nc 208.100.2.25 23

Answer: B,C