I believe the answer is c hope this helps!
Answer: 1 stands for Arabia
2 stands for Egypit, Persia, and Syria
3 stands for Spain and Berbers
or
1 stands for At the death of Muhammad, 632
2 stands for After the conquest of the first four caliphs, 661
3 stands for After the conquest of the Umayyad caliphs, 750
Although this is slightly subjective, it would be "William Shakespeare" who is considered the greatest playwright in the English language, due mostly to his incredibly fluid and "natural" style.