Its either C or D, but C seems closer.
I'd go for letter D) . But your teacher probably wants to hear letter A) or at least C)
They do this because back then, a lot of things happened in ancient Greece. So because so many things happen, they have to carefully study the events and place them in a category or order in order to make sense.<span />
<span>it helped the islamic empire expand without using violence. </span>