Which two of these statements about SMTP and ESMTP are the most correct?

Which two of these statements about SMTP and ESMTP are the most correct? (Choose two.)

A.
Open mail relays are often used for spamming.

B.
ESMTP does not provide more security features than SMTP.

C.
SMTP provides authenticated e-mail sending.

D.
Worms often spread via SMTP.