Explanation:

Types of Scanning:
1) Xmas Tree Scan
2) Cloud Scan
3) Null Scan
4) SYN Stealth

Not a Type of Scanning:
The option 'B' which is "Cloud Scan" is not a type of scanning.

Explanation:
1) Xmas Tree Scan: It is a type of scanning where all the flags in the TCP header are set to 1. This includes the URG, ACK, PSH, RST, SYN, and FIN flags. This type of scan is used to test the security of a network by sending packets with all flags set to 1 and analyzing the response.

2) Cloud Scan: This option is not a type of scanning. It might have been included as a distractor in the question. "Cloud Scan" is not a recognized term in the field of network scanning.

3) Null Scan: It is a type of scanning where no flags are set in the TCP header. This type of scan is used to probe a target system to check if it is listening on a specific port. If the target system does not send any response, it indicates that the port is closed. If the target system sends a response with a RST flag, it indicates that the port is open.

4) SYN Stealth: It is a type of scanning where only the SYN flag is set in the TCP header. This type of scan is used to determine if a port is open or closed. If the target system responds with a SYN/ACK packet, it indicates that the port is open. If the target system responds with a RST packet, it indicates that the port is closed.

In conclusion, the option 'B' which is "Cloud Scan" is not a type of scanning. The other options mentioned, namely Xmas Tree Scan, Null Scan, and SYN Stealth, are all recognized types of network scanning techniques.