One way Qin Shihuangdi united China was by

A.

making his subjects write in the same way.

B.

asking his enemies to live with him.

C.

forcing everyone to change their names.

D.

enslaving people to build things for him.

A. Making his subjects write in the same way.

Explanation:

Qin Shiguandi promoted the use of a common language, written and spoken, as the most powerful motor of the Chinese unification in the mid-3rd Century B. D, along with the unification of weights and measures, the establishment of a centralized administration and construction of roads throughout territories. Hence, the right answer is A.