Brainliesttt list the greatest achievement of each explorer: -francisco pizarro: -vasco da gama:

Francisco Pizarro:  "discovered" the Incan empire and conquered it brutally and quickly, stealing immense hoards of gold, silver, and other treasures. Although that is horrible It made way for many cultures around today.

Vasco da Gama:  Vasco da Gama linked Europe and Asia through an ocean route for the first time this later helped the development of many asian countries.

c or d both can be the answer