Answer:
D. They created a standard system of writing that has influenced modern Chinese.
Step-by-step explanation:
China has a really large region. Even among people within the same region, the way people talk and write could differ from one another.
This made it hard for fellow citizens from different region to communicate with one another.
IN 221 bc, Qin created a standardized system of writing under the rule of Qin Shi Huang. This standard help destroying the communication barriers that exist between different regions.
This caused trades to flourish within the regions. On top of that, it also provide more opportunities for people in China to learn and pursue higher education to move up their social strata.