In tim o'brien's "ambush," which element directly enhances the theme of the past's imprint on the present?

a) the frame-story structure
b) the character kiowa
c) the reference to fatigue toxins
d) the inability to discuss war nextreset

A) the frame-story structure.

A frame story is a narrative that is presented as a way to contain a second, more developed story (or series of stories). In this case, O'Brien receives a question from his daughter, Kathleen. She asks him whether he ever killed anyone. This story leads us to a second story, in which O'Brien reflects on his past and his role in the war. The use of a frame story structure enhances the theme that the past can leave a strong imprint on the present.

c is the correct answer