Final answer:
Christopher Columbus is the explorer credited with opening the floodgates to exploration in the Americas, after his 1492 voyage was financed by Spanish monarchs. Pedro Cabral was the first explorer to claim Brazil for Portugal. so, option A is the correwct answer.
Step-by-step explanation:
Explorers of the Americas
The explorer who opened the floodgates to exploration in the Americas was Christopher Columbus. Sponsored by the Spanish monarchs, Isabella I of Castille and Ferdinand II of Aragon, Columbus landed in the Caribbean in 1492. While he mistakenly believed he had reached the Indies, his discovery nonetheless spurred an era of European exploration in the New World. Inspired by the potential for wealth and land, other Spanish explorers followed, including Hernán Cortés, who conquered the Aztec Empire, and Francisco Pizarro, who conquered the Inca Empire.
Regarding the exploration of Brazil, the first explorer to reach Brazil and claim it for the throne of Portugal was Pedro Cabral. Unlike Columbus, Cabral intentionally set sail for India but ended up on the coast of Brazil in 1500, subsequently claiming it for Portugal. This act contributed to the expansive Portuguese empire in South America.