Final answer:
The Chinese government's decision to cease exploration in the Indian Ocean in the early 15th century was primarily driven by fiscal and security concerns. Internal disputes, external frontier threats, and financial issues gravitated the government towards an inward focus.
Step-by-step explanation:
The Chinese government made the decision to halt explorations in the Indian Ocean during the early fifteenth century predominantly due to option (d): Government concern with domestic problems and frontier security. After the Ming Dynasty completed impressive voyages under the leadership of Zheng He, fiscal issues, succession disputes, as well as challenges with frontier security started dominating the government's concerns.
External threats, especially from the northern frontiers, as well as internal problems were pushing the Chinese government towards a more inward orientation. These factors collectively contributed to a shift in focus towards domestic issues and border security, leading to the decision to halt voyages.
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