Final answer:
Spain, Portugal, and other European countries were competing to establish a sea route to the Indies, primarily driven by the desire to participate in the lucrative spice trade and to expand global trade under the mercantilist economic system.
Step-by-step explanation:
Spain, Portugal, and other European countries were primarily in competition to fund A) A sea route to the Indies. During the Age of Exploration, these nations were driven by mercantilist ambitions to find new trading routes and resources. The lucrative spice trade with Asia was especially appealing because it would enrich the nation that established contact and also divert trade from overland routes controlled by Muslim traders to European sea routes, thus weakening the Muslim world. This era also saw the Treaty of Tordesillas, which divided the unclaimed world between Spain and Portugal, initiating the colonization of the Americas, the Caribbean, and parts of Africa and Asia by the Europeans in the 17th and 18th centuries. Their exploration led to the establishment of colonies, expansion of global trade, but also the spread of diseases and the exploitation of indigenous populations.