PHP can indeed send e-mails of any valid format using the mail
function, making
communication with the MTA directly from PHP code using SMTP a poor
choice.
Additional headers at the top of the e-mail must be added as a string
using the
$additional_headers parameter, with each header ending with both a
newline and linefeed
character (\r\n). When sending complex e-mails, such as ones with file
attachments and/or
HTML-formatted text, not only must additional headers be added, but
MIME-specific
headers must also be included in the $message portion of the e-mail
itself, so answer E is
correct.