As per your comments on xml, I tried to post the xml in comment.
Somehow the xml is not considered as valid text (probably due to security).
So, here is the sample xml with question, answer and correct flag.
<samplepaper>
<question id="1" description="What is the capital city of India?">
<answer id="1" description="Mumbai" flag="0" />
<answer id="2" description="Kolkata" flag="0" />
<answer id="3" description="New Delhi" flag="1" />
<answer id="4" description="Chennai" flag="0" />
</question>
<question id="1" description="XML can be parse using?">
<answer id="1" description="xmlparse" flag="0" />
<answer id="2" description="XmlDoc" flag="0" />
<answer id="3" description="XMLGrabber" flag="0" />
<answer id="4" description="XMLDocument" flag="1" />
</question>
</samplepaper>
Flag=1 is correct answer
Flag=0 is incorrect answer
cheers