The correct answer is: “Cheap imports from Japan was a cause of slow technological growth in China during the time period of 1600–1800.”
Japan’s Toshimune encouraged technology transfer in agriculture, relying on Chinese immigrant expertise. This relaxed "sakoku" rules and allowed the import of Chinese botanical texts. !853 was a turning point for both countries, the exposure to the West afforded both countries an opportunity to increase interaction and Japanese traders started to appear in Shanghai aboard British and Dutch ships.
It was on July 1871 that both countries signed a commercial trade treaty.