A summary is something that 'sums' up the story in a paragraph for few sentences. So B. Essentials of the story to kind of sum it up. Having all details doesn't really 'sum' the story up. Your just telling us the whole story again.
The answer is B. It is like giving an overview of the story without going into too much detail, and it shouldn't include your opinion. It should simply summarize the information included in the story.
