Who attempted to seduce Denny during a vulnerable time?

The correct answer is Annika. Throughout "The Art of Racing in the Rain," Annika's character is portrayed as having a complicated relationship with Denny, particularly during moments of vulnerability in his life. When Denny faces challenges, especially after the loss of his wife, Annika sees an opportunity to pursue him romantically. Her attempts are highlighted during this emotional period, making her actions significant in the context of the story.

Trish is never depicted as attempting to seduce Denny; her role is more aligned with being a part of his life at a different stage. Eve, Denny's beloved wife, is not involved in any seductive context since her character is focused on her relationship with Denny rather than any outside influences. Zoë, their daughter, is a child in the narrative and cannot engage in romantic or seductive behavior, making Annika the only character fitting this context.