A. FTP
B. SMTP
C. HTTP
D. HTTPS

Solution

A. FTP

Explanation

<ul><li><span style="font-size: 14px;">FTP is used to upload and download files between a client and a server over a network.</span></li><li><span style="letter-spacing: 0.01rem;">It operates on the TCP/IP protocol suite.</span></li><li><span style="letter-spacing: 0.01rem;">Typically uses port 21 for control commands and port 20 for data transfer.</span></li></ul>