I think it is C, because it begins with short syllables and ends with a long one.
A backstory for your character is like background information for a character. When you write details about a character before you write your story, you are then able to use these details later on to help you improve your writing. You are able to incorporate their likes, dislikes, childhood, friends, family & more all into what you're writing. Its easier to come up with these earlier on than during your writing.
Answer: the correct answer is a. Onomatopoeia
Explanation: Onomatopoeia means the use of sounds associated with what is mentioned.