The most accurate answer is:
A. The Qing wanted to help unify the country and thought adopting existing ideas and the dominant culture would help with this.
The Qing rulers, being a Manchu dynasty that ruled over a predominantly Han Chinese population, understood the importance of integrating into and appealing to the Han culture. By adopting Han customs, culture, and government systems from earlier dynasties, they aimed to legitimize their rule, promote stability, and foster unity across the diverse regions of China.