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Answer:
Monarch butterfly migration is the phenomenon, mainly across North America, where the subspecies Danaus plexippus plexippus migrates each summer and autumn to and from overwintering sites on the West Coast of California or mountainous sites in Central Mexico. Other subspecies perform minor migrations or none at all. This massive movement of butterflies has been called "one of the most spectacular natural phenomena in the world".[1]
B is your answer to your question
