Exam 312-49v10 topic 1 question 161 discussion

The answer seems to be C, SFTP (Secure File Transfer Protocol) uses net port 22, however, after revealing the correct answer, I was surprised. So, what is the difference between these two answers? For net port 22, the overall idea is that George is gonna look at all traffic through port 22, however, looking at src/dst 22 - this means that George is gonna look only at all traffic that comes from port 22 and goes only to port 22. Probably I did not understand the question correctly, but if the question states that George wants to see the communication of colleagues who has open port 22 and communication through this port - then the answer is okay, however, net port 22 also do the same and also covers other options that if his boss is communication with src = 22 and dst = other port -- Which is also possible