Final answer:
Option (a), Vasco da Gama was the explorer who fulfilled Portugal's goal of finding a sea route to Asia by sailing to India. Pedro Cabral was the first to reach Brazil and claim it for Portugal.
Step-by-step explanation:
The individual who fulfilled Portugal's goal of finding a sea route to Asia was Vasco da Gama. In 1497, Vasco da Gama set sail from Portugal, rounded the Cape of Good Hope, and successfully reached the subcontinent of India, thereby becoming the first European to do so by sea. This historic voyage enabled Portugal to participate in the lucrative spice trade, which had until then been dominated by land routes controlled by Muslim traders.
On the other hand, the first explorer to reach Brazil and claim it for the throne of Portugal was Pedro Cabral. Although Christopher Columbus had set out with the aim of finding a westward route to Asia, it was later confirmed by the voyage of Ferdinand Magellan that Columbus had instead reached a previously unknown land mass, which would come to be known as the New World.