Answer:
<h3><em>Khmer usually live in Cambodia, Thailand, and Vietnam.</em></h3>
Answer:
Correct answer is A. Determine the resource's original medium of production.
Explanation:
A is correct answer because it is important to know how reliable the source - is it forged or not, and its validity - to see if the information contained there are true.
B is wrong because it is not important who the author is, but is he reliable enough.
C is wrong because it doesn't matter how many time the resource has been published, if it is not reliable.
D is not important, because idea itself is not telling us enough about its importance and validity.