Which choice most often caused the spread of Islam throughout southeast Asia during the thirteenth through seventeenth centuries?
A. trade
B. military action
C. Missionary's
D. nomads

The answer is B. In South Asia, Islam found a place in a long-established civilization as invasions by Turkic-speaking warrior groups from Central Asia, recently converted to Islam, brought the faith to northern India. Thus the Turks became the third major carrier of Islam, after the Arabs and Persians, as their conquests initiated an enduring encounter between Islam and a Hindu-based Indian civilization.