Which port or ports are used for SMTP?

Which port or ports are used for SMTP?

A.
20 and 21

B.
25

C.
53

D.
161 and 162

Explanation:
SMTP uses port 25.
Incorrect Answers:
A: 20 and 21 are used for FTP.
C: 53 is used for DNS
D: 161 and 162 are used for SNMP
1D0-470