The answer is B. because this is the only answer that is an immediate call to action for the situation, instead of just telling you facts like the other answers, this answer tells you straight up what you should do.
Answer: <u><em>The external conflict is between Bob Ewell and Atticus... This is a man vs man conflict and it happens several times in the book...</em></u>
Hope this helps!!
I´d say A. Others don´t make much sense in the context.
Formal is like writing to professors. like this, The other day I was with a couple of friends at a cinema. After watching the film the Manager came towards us.... ect ect