The correct answer is the "Open door policy led many nations to carve out spheres of influence in China, which blamed imperialists."
At its core, the Boxer Rebellion was an anti-colonial, anti-Christian, and anti-foreign uprising. The Boxers, who consisted of militant Chinese citizens, did not like that European countries were trying to change Chinese society. The economic influence of these countries made Chinese citizens worry that their would also be social, political, and other economic changes.