What new business practices did the merchants introduce in muslim lands ?

Merchants built a vast trading network across most of the Muslim lands and introduced many business practices that helped Muslim lands to prosper and become rich. Merchants introduced many different cultures upon travelling from one place to another for trade. Merchants introduced the ideas of banking along with partnerships. Merchants also brought the Indian number system, which spread to Europe and Muslim lands, later came to be known as Arabic numerals.  

answer; /// i believe that the correct answer is (b)///they gained vast amounts of

no options provided, here,but the answer to this question is often: a historian cites a japanese newspaper article published a year after the end of world war ii in order to draw conclusions about the effect of the war on the japanese economy.

clearly from the answer, the historian alludes to historical sources,and records to aid in analyzing and drawing conclusion on the effect of the war on the economy of japan.