Select the most appropriate one-word substitution for the given group of words. 

Writing of one's own life story 

Autobiography

The most appropriate one-word substitution for the given group of words "Writing of one's own life story" is "Autobiography".

Explanation of the options:

1. Autobiography: An autobiography is a written account or narrative of a person's life story, written by themselves. It is a first-person account that covers various aspects of their life, including personal experiences, achievements, and challenges.

2. Biography: A biography is a written account or narrative of a person's life story, written by someone else. It is a third-person account that provides an overview of the person's life, including their background, achievements, and impact.

3. Ode: An ode is a type of lyrical poem that expresses strong emotions and often praises or glorifies a person, event, or thing. It is not directly related to writing one's own life story.

4. Preamble: A preamble is an introductory statement or preliminary explanation that precedes a document or text. It is not specifically related to writing one's own life story.