Read the text carefully and then answer the questions by choosing the correct answer!
Once upon a time, in a faraway kingdom, there was a young princess named Lily. She lived in a magnificent castle surrounded by beautiful gardens. Despite her luxurious life, Lily often felt lonely. Her parents, the king and queen, were always busy with royal duties, leaving her with only servants for company. One day, as she wandered through the castle's halls, she stumbled upon a hidden staircase leading to a secret garden. Inside, she discovered a magical fountain guarded by a mysterious old oak tree. With each drop of water from the fountain, the tree whispered ancient tales and enchanted melodies. From that day on, Lily would visit the secret garden whenever she felt lonely, finding solace in the tree's stories and songs.
What is the main setting of the story?