Which f the following is ture regarding the expanse of the islamic empire, before 1400

Phase I: Early Caliphs and Umayyads (610–750 CE) Within the century of the establishment of Islam upon the Arabian peninsula and the subsequent rapid expansion of the Arab Empire during the Muslim conquests, one of the most significant empires in world history was formed.

This period is traditionally said to have ended with the collapse of the Abbasid caliphate due to Mongol invasions and the Siege of Baghdad in 1258 AD. A few contemporary scholars place the end of the Islamic Golden Age as late as the end of 15th to 16th centuries.

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your answer would be (a)