How was the title of sultan, a common title for a muslim ruler, first used and with whom?
a. mongol batu khan as he led mongol empire.

b. emporer constantine, as an honorarium from the people of constantinople

c. seljuck leader beg led the seljuck turks yet remained loyal to the abbasid caliph in baghdad so another title of leadership was instated.

d. ghaznavid ruler mahmud spread islam deep into india yet didn't hold power long.