Final answer:
The details given do not specify the exact reason for Da Chen's train ride, but thematic elements suggest seeking new opportunities (Option C) aligns with the other historical and literary references.
Step-by-step explanation:
The question pertaining to Da Chen's train ride does not provide enough context within the provided information to confidently determine the purpose of his journey. However, we can extrapolate from the related historical examples presented. The references to various historical and literary figures such as Gil-Dong and Zheng He, as well as the experiences of Chinese immigrants, display themes of seeking freedom, new opportunities, and engagement with the wider world outside one's immediate circumstances. Literature and history often depict train journeys as transitions into new phases of life or as escapes into broader horizons. Without additional context, it's plausible to infer that Da Chen's train ride might be associated with a pursuit of new opportunities or a search for freedom similar to the characters in the examples, aligning with option C, to seek new opportunities. However, without the specific text or backstory for Da Chen, this remains an educated guess based on thematic consistency rather than a definitive answer.