The most probable answer here I tihnk is C - flasback of events.
An autobiography isn't suppose to convery a sorrowful tone, so this answer is surerly not correct.
Some autobiographies might convey significance of fame in certain ways, however, that is not the main idea of what a autobiography is suppose to do.
Some also might include a sigificant message or lesson. Again, however, that is not what an autobiography is supposed to be.
The truly correct answer in this case is C - flashback of events, as an author is supposed to write relatively detailed descriptions of certain points in his life that he found to be important in his life :)