the answer is a, he miscalculated, since the Americas hadn't been discovered by europeans (the native americans were there first) they did not account for america in their calculations
the answer is a ;
Columbus thought he had reached Asia because he miscalculated the size of the Earth, believing the distance from Europe to Asia was much shorter than it actually is. He also mistook the lands he discovered in the Americas for islands near Asia, especially after interacting with the indigenous peoples. Therefore, the correct answer is A: He miscalculated the size of the Earth by more than half.
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