Self Check

Which internal DTD specifies the structure of the following XML document?

  1. <!DOCTYPE Messages [
    <!ELEMENT Messages (mail)>
    <!ELEMENT mail (subject)>
    <!ELEMENT mail EMPTY>]>
  2. <!DOCTYPE mail [
    <!ELEMENT Messages (mail)>
    <!ELEMENT mail (subject)>
    <!ELEMENT subject EMPTY>]>
  3. <!DOCTYPE Messages [
    <!ELEMENT Messages (subject)>
    <!ELEMENT mail (subject)>
    <!ELEMENT subject EMPTY>
  4. <!DOCTYPE Messages [
    <!ELEMENT Messages (mail)>
    <!ELEMENT mail (subject)>
    <!ELEMENT subject EMPTY>

The correct answer is:

  1. <!DOCTYPE Messages [
    <!ELEMENT Messages (mail)>
    <!ELEMENT mail (subject)>
    <!ELEMENT subject EMPTY>