In the given question, a statement of Assertion is followed by a statement of Reason. Mark the correct answer.

Assertion: Al Biruni, in his account, attempted to suggest that social divisions were not unique to India.
Reasoning: In his writings, Al Biruni mentioned that in ancient Persia, four social categories were recognized.

Both the Assertion and the Reason are correct and the Reason is the correct explanation of the Assertion.

Al-Biruni tried to explain the caste system by looking for parallels in other societies. He noted that in ancient Persia, four social categories were recognised: those of knights and princes; monks, fire-priests and lawyers; physicians, astronomers and other scientists; and finally, peasants and artisans. In other words, he attempted to suggest that social divisions were not unique to India. At the same time he pointed out that within Islam all men were considered equal, differing only in their observance of piety.