A description of a question/answer or of just an answer or answer set. The explanation may describe, for example, why this particular answer is incorrect, or where in the text the material for this question can be found, et al.
<!ELEMENT explanation %explanation-model; >
(p)+
Multiple choice style question:
...
<sec id="sec45">
...
<question-wrap>
<question><p>Where was the first permanent English
settlement in the New World?</p></question>
<answer-set answer-type="multiple-choice">
<answer correct="no">
<label>A</label>
<p>Plymouth</p>
</answer>
<answer correct="yes">
<label>B</label>
<p>Jamestown</p>
</answer>
<answer correct="no">
<label>C</label>
<p>Roanoke</p>
</answer>
<explanation>
<p>Established by the Virginia Company of London, Jamestown
was the first permanent English settlement in the New World;
it flourished from 1607 to 1699. Although the Roanoke colony
was founded earlier (in 1587), that colony failed; upon returning
from a trip to England for supplies, its Governor found the
settlement abandoned. Although one of the earliest New England
colonies, Plymouth (in modern Massachusetts) was not founded
by the Pilgrims until 1620.</p>
</explanation>
</answer-set>
</question-wrap>
</sec>
...
True-False style question:
...
<sec id="sec45">
...
<question-wrap>
<question><p>Peregrine White was the first English
child born in North America.</p></question>
<answer-set answer-type="true-false">
<answer correct="no">
<p>True</p>
</answer>
<answer correct="yes">
<p>False</p>
</answer>
<explanation>
<p>The first English child born in North America was
Virginia Dare. She was born in August 1587, in the
short-lived colony of Roanoke. Although the settlement
was later abandoned and the fate of its inhabitants a
mystery, records brought to England by her grandfather,
the governor of the colony, later in 1587 note her birth
and baptism. Born in November 1620, Peregrine White
was the first child born in the Plymouth colony.</p>
</explanation>
</answer-set>
</question-wrap>
</sec>
...