One of the Roman Empire's important achievements was: A. ending the practice of slavery.
B. becoming the first polytheistic empire.
C. creating influential art and writing.
D. offering all people religious freedom.

Correct answer is C. creating influential art and writing.

Explanation:

Option A is not correct answer as slavery existed in Rome until the last days of existence.

Option B is not correct as most of the Empires before the Roman were polytheistic, including Egyptian, Assyrian...

Option C is correct as Roman artists and writers made a large impact on European art, especially in the period of Renaissance.

Option D is not correct as in certain period Romans were not allowing religious freedom. The best example for that is Christianity until the 4th century.

it provided for equal trade rights among nations in china.