SFTP VS FTP TLS/SSL question

mgmguy1

Question, In the Techexams Technotes it says
The Secure File Transfer Protocol (S/FTP or SFTP) allows you to implement the same functionality as regular FTP, but much more secure. SFTP is essentially FTP over SSH (Secure Shell), hence provide the same level of security as SSH. This includes mutual authentication based on digital certificates, and establishing a tunnel between the client and the server through which data is transmitted in an encrypted form. Another mentionable advantage is that SFTP operates over the same port as SSH (port 22) and does not require port 20 and 21 to be open as with regular FTP.

So using SFTP seems to be the way to go so why is SFTP listed in the exam objectives and not port
989/TCP,UDP FTP Protocol (data) over TLS/SSL & 990/TCP,UDP FTP Protocol (control) over TLS/SSL

I would think that if you are connecting to a secure FTP site, that SFTP would be used unless Port 989 and Port 990 are legacy ports ??

Please advise.