The invention of the compass allowed for new maritime trade routes
Simple, the Americas had gold and silver. The Spaniards basically craved metals like those. Also because of the inquisition, they wanted to convert the natives to Christianity. Since the Spaniards were not a powerful economy at the time. The riches made their economy SKYROCKET.
Answer:
The theory was that Polynesia “lay within the range of pre-European mariners from South America.” Now go and get that A+ :)