To answer this question, we need to identify the country that is located in western Europe, borders only Spain, and has a history of being the birthplace of many great explorers.
Option A) Gibraltar - This option is incorrect. Gibraltar is a British Overseas Territory located on the southern coast of Spain, so it does not border only Spain.
Option B) Portugal - This option is correct. Portugal is located in western Europe and shares its only land border with Spain. Portugal has a rich history of exploration, with famous explorers like Vasco da Gama and Ferdinand Magellan originating from the country.
Option C) Morocco - This option is incorrect. Morocco is located in North Africa and does not share a border with Spain.
Option D) France - This option is incorrect. France is located in western Europe, but it shares borders with multiple countries, not just Spain.
The correct answer is Option B) Portugal. Portugal is the country located in western Europe, bordering only Spain, and known for being the birthplace of many great explorers.