SMTP Is Not Concerned with the Format or Content of Messages,except

SMTP is not concerned with the format or content of messages,except for two exceptions.Which two of the following are these exceptions?

A) SMTP standardizes the message character set as 7-bit ASCII.
B) SMTP standardizes the message length into multiples of the the packet size.
C) SMTP checks for virus content.
D) SMTP adds binary attachments to the content,when present.
E) SMTP adds log information to the start of the delivered message that indicates the path the message took.