ANSWER: A. By questioning whether their sources are reliable.
EXPLANATION: Early historians used unreliable sources to write history. They had to believe mainly on sources which were believed by people. Modern day historians has many instruments and theories to prove an incident of history. Scientific advancements has helped calculate the accuracy of any event. Carbon dating is one of the many scientific advancements helping modern day historians. This test helps them to find out the age of any fossil found, thus giving an accuracy and reliability of the sources which will be documented.
A because you always have to make sure that the sources your using is reliable because if not then what use is it if it gives you the wrong stuff. I hope I helped :)
The best option from the list would be that "<span>b. He was successful in unification of the norther third and administered it with help from local rulers," since this kept down local insurrections. </span>
