Final answer:
The information provided suggests that Sahomi dances mainly to preserve Japanese culture, as indicated by the context of Shosagoto plays that emphasize dance for storytelling.
Step-by-step explanation:
The question concerns the motivations behind why Sahomi dances. Based on the information provided, the options include earning money, preserving Japanese culture, competing with other dancers, and pleasing her family. While financial benefits and competitive aspects are mentioned in the context of the Wodaabe's geerewol and yaake dances, and a Rwandan girl dances with a basket on her head as part of her culture's tradition, these details do not directly answer why Sahomi dances. However, the reference to 'Shosagoto plays,' which are Japanese in origin and rely heavily on dance to convey the narrative, suggests that the primary motivation for Sahomi could be related to preserving Japanese culture through dance, as the plays are known for emphasizing dance over dialogue.