Eriene had passed her first test, the dragon no longer a threat to the kingdom's way of life. Wisps of smoke drifted up from the land that its poisonous breath had burned. Soon, new grass would poke through, and memories of the battle would recede into the past. But Eriene knew this was not the end. This dragon lay slain in the Yonderland. But its spirit would return again and again in different forms. Which of the following is most likely a theme of the story?

A
Evil can easily be defeated.

B
Good people are difficult to find.

C
Good and evil always exist together in the world.

D
People often forget the things they don't want to remember.