According to local tradition, Sultan Abu ibn al-Hasan founded the East

Source: McGra Hill GMAT 2013

According to local tradition, Sultan Abu ibn al-Hasan founded the East African trading state of Kilwa in the mid-tenth century. Professor Ascalon, however, argues that
Sultan al-Hasan did not rule in Kilwa until at least a century later.

Which of the following, if true, provides the strongest support for Professor Ascalon’s position?

A. The Hunsu Kubwa Palace, the largest stone structure in sub-Saharan Africa prior to the eighteenth century, dates to the rule of Sultan Sulaiman in the fourteenth century.
B. The oldest mosque on the island, which has traditionally been attributed to the reign of Abu ibn al-Hasan, has a foundation dating to ca. 800 C.E.
C. The Kilwa Chronicle, a document based on Kilwa oral history that has been shown to be unreliable on matters of chronology, dates the rise to power of Sultan al-Hasan to the
year 957 C.E.
D. Silver and copper coins bearing the name of Abu ibn al-Hasan have been found in archeological sites dating from the late eleventh to the fourteenth centuries, but none
have been found in sites dating earlier than the late eleventh century.
E. Archeological records suggest that the island of Kilwa enjoyed a period of economic prosperity beginning in the mid-eleventh century.