Which element of a story provides the strongest clues about the story’s theme? the characters
the setting
the plot
the style

The plot.

Explanation:

The plot is the structure of a story, with all the complications and causal connections within it. It develops as a sequence of events in a story where each event causes or leads to another. These are not unrelated, accidental events: the events are related to the conflict, the struggle the protagonist goes through to achieve his dramatic goal.  

Usually a story starts with the exhibition, in which the main characters are introduced within a certain setting and situation. Then the plot is further developed through action and dialogues. The writer or screenwriter often makes use of so-called plot points in the structure and evolution of his story, points that will prove to be important in the story.

 However, a plot of a book, movie or play can also be described with the intention of making explicit how the characters' actions direct the story. Only the actions and events that are important for the construction of the story are described.

a.) literature that explores grotesque characters and eerie, violent occurrences in a dreary setting.

the answer is "began" because it is a action that can be done