Answer:
B. add another perspective to the story.
Step-by-step explanation:
In "The Strange Case of Dr. Jekyll and Mr. Hyde," the author Robert Louis Stevenson includes Dr Lanyon's letter together with Jekyll's letter when Utterson and Poole find Hyde's body in Jekyll's clothes. Thus, the men read Lanyon's letter first, in which he describes the shock that he felt when he saw Hyde transform into Jekyll in front of him and how such metamorphosis deteriorated his health. As a result, the story is told in another scientist's viewpoint before Jekyll reveals the truth in the first person by the end of the story.