Answer:
B. A strong loyal military
Step-by-step explanation:
The three Islamic empire's of the medieval times are the Mughal, the Safavid, and the Ottoman and all three had similar cultural background that was Turkish-Mongolian in nature.
The common factor between all three dynasties was that they were Muslim, had an agrarian economy and paid their soldiers in land grants.
A strong loyal military was central to maintaining and expanding all three islamic empires