Correct Answer:
C. Barcelona
The correct answer is Barcelona. La Sagrada Familia is located in Barcelona, Spain. Designed by the renowned Catalan architect Antoni Gaudí, this iconic basilica has been under construction since 1882 and remains incomplete. It is one of the most visited landmarks in Spain and a UNESCO World Heritage Site. The basilica's intricate façades and towering spires make it a masterpiece of modernist architecture. Madrid is the capital of Spain, Granada is known for the Alhambra, and Seville is famous for its cathedral and Alcázar, but none of these cities are home to La Sagrada Familia. Barcelona, the capital of Catalonia, is the only correct location for this architectural wonder.