Use the Passage Below to Answer All Parts of the Question

Use the passage below to answer all parts of the question that follows.
Answer all parts of every question. Use complete sentences; an outline or bulleted list alone is not acceptable. Label each portion of the question separately and clearly as you complete your answer.
"When in 1421 the Ming rulers of China changed their capital city-leaving Nanking, and moving to Peking, in order to face the dangers of the Manchu and Mongol frontier-the massive world economy of China swung round for good, turning its back on a new form of economic activity based on ease of access to sea-borne trade. A new landlocked metropolis was established deep into the interior and began to draw everything toward it. Whether conscious or unconscious, this choice was decisive. In the race for world dominion, this was the moment when China lost her position in a contest she had entered without fully realizing it, when she had launched the first maritime expeditions from Nanking in the early fifteenth century."
Fernand Braudel, The Perspective of the World: Civilization and Capitalism, 1992
(A) Identify and explain ONE change or development from
c. 1200 CE to 1450 that would support the author's assertion in the passage above.
(B) Identify and explain ONE change or development from
c. 1200 CE to 1450 that would challenge the author's assertion in the passage above.
(C) Identify and explain ONE foundational cultural reason that could be used to justify the actions taken by Ming rulers.