Test analysis: This question mainly examines students' ability to accurately interpret material information and analyzes materials. According to the material information that "the Qing army besieged Anqing and fled without fighting, and northern Anhui returned to the Taiping Heavenly Kingdom", it can be inferred that the war in the material refers to sanhe town's victory. According to the knowledge learned, sanhe town's victory made the situation in the upper reaches of Tianjing stable, so B meets the meaning of the question, so B is chosen.