C

Test question analysis: Gu Yanwu was an anti-feudal democratic thinker during the Ming and Qing Dynasties. He believed that a gentleman's pursuit of knowledge was to enlighten the world and save the world, but it was useless to talk about poetry, philosophy, and governance. This shows that Gu Yanwu advocated "managing the world for practical application" and advocated seeking true knowledge through practice. A, B, and D are all inconsistent with Gu Yanwu’s claims in the material, so choose C.