Answer:
Option D. To comment about an issue facing society
Explanation:
There are many definitions of <em>theme</em>. But most of them have most of the point common.
Theme may be defined as <em>"It is deeper meaning of the story running beneath the surface meaning of the story/poetry etc. I helps reader understand the deeper meaning of the story and understand some aspects of human conditions" </em>
Literature has always been considered mirror of life - it reflects our society either directly (Geoffrey Chaucer's Canterbury Tales) or indirectly (Keats' "The Fall of Hyperion: A Dream). So in most cases the purpose of the theme of a literary work is to comment about an issue faced by society.
Option A is not correct because main element of theme's definition is missing in it i.e human conditions, society.
Option B is not correct also because elements of mystery and surprise are not integral parts of a literary work, while theme is an integral part.
Option C is also not correct: There's no doubt that author's life experiences shape his/her style of writing and the themes he or she chooses for his/her work. But theme is not just about author's life experiences - it is about society's life experiences.
