The statement that best describes the effect of narration on the story is The narration suggests mounting helplessness and agony.
Explanation:
The full description of the scene in this excerpt from "The Adventure of the Mysterious Stranger." shows a person who does not have any hope, this can be explained with the use of the words " lying on his face", "his whole countenance bearing traces of the convulsions of his mind" añtpgether gives the reader the impression of helplessness.
