4. Nanping City, Fujian Province vigorously develops aquaculture, uses chicken manure to produce bio-organic fertilizer and generate electricity, and uses chicken feathers and chicken intestines to produce high-protein fish feed. Chicken manure, "Not only does it not pollute the water source, but it can also bring tens of millions of yuan of output value every year" reflects the coordinated development of economy and nature, so D is chosen. To promote the coordinated development of economy and society, we should not only focus on economic construction, but also promote the development of political, cultural and social construction, so C has nothing to do with materials.