Which of the Following Was a Major Milestone in the Reign

Which of the following was a major milestone in the reign of Ferdinand and Isabella of Spain?

A) The monarchs became politically isolated in Europe as other monarchs refused to make alliances with these "new" rulers.
B) The last Muslim stronghold in Spain-Granada-fell to Christian forces.
C) Spain instituted broad religious toleration so that Jewish learning and finance could be used to support naval exploration.
D) The Spanish economy oriented itself toward the Mediterranean to take advantage of new trade with the Ottoman Empire.