Which group of people held the largest land empire in the world?

Mongol Empire

The Mongol Empire existed during the 13th and 14th centuries and it is recognized as being the largest contiguous land empire in history.

Explanation:

answer; ///i do believe that the correct answer is (d); ///athens had a small population;

2018 means 2018 ce or common era

there have been other eras too including bce, which included way more years.