Answer:
A. A man of disreputable nature.
Explanation:
Just by looking at the question and answers, you can determine that the most formal statement is A. A man of disreputable nature. By the use of the word formal, people tend to think of respectful/professional words/things. The words shady character and snake in the grass are more of a casual/informal way of describing a "suspicious" person.
You would add key events. Summaries are basically condensing down a story or a book or an essay so it’s shorter, so To get the idea of the book you need to have the key events.
