c. The North placed a blockade on southern ports and wanted to take over Richmond while the South focused on fighting a defensive war. is your answer
The North followed the Anaconda Plan, which was to slowly squeeze the South of her resources, before striking the final blow.
The South tried to use the diplomacy plan, which was to ally themselves with European countries (& using cotton as the reason), to be able to get equipment, resources, and extra funding for themselves to win the war.
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