Which of the following services use UDP?

Which of the following services use UDP? (Choose three.)

A.
Telnet

B.
TFTP

C.
SNMP

D.
DNS

E.
SMTP

F.
HTTP

Explanation:
Common TCP/UDP ports:
TCP ports:
20 FTP data
21 FTP control
23 Telnet
25 SMTP
53 DNS
80 WWW

100 POP3
UDP ports:
53 DNS
69 TFTP
161 SNMP
NotE. DNS use TCP for regional transmission, and use UDP for name inquiry.