The answer is C. Spain. When Prince Ferdinand of Aragon married his cousin Princess Isabella of Castile, it was now possible to join the two kingdoms and this brought stability to the country. Catholicism became the main religion of Spain and they sponsored explorations to search new lands. A good example of this was when Queen Isabella supported Christopher Columbus for his voyage in 1492. They also acquired several territories and their children married other monarchs in Europe. Under their reign, Spain grew in power.