Final answer:
Scout and Jem discover that their father, Atticus Finch, is an expert shot with a rifle. This revelation is supported by the narrative and the crowd's expectation of his marksmanship skills when he shoots a mad dog.
Step-by-step explanation:
Scout and Jem find out that their father is an expert shot with a rifle when he had to kill a mad dog. This discovery comes as a surprise to them, showing a side of their father they have not previously known or seen. This skill is evident during the tense situation in which their father is able to take down the threat with precision, underlining the fact that he possesses a higher level of proficiency with firearms.
The referenced texts describe various instances involving rifle shooting which showcase the importance of accuracy, skill, and experience. These passages help us understand the significance of being a skilled marksman in critical situations. Whether it is avoiding getting shot, the anticipation of expert gunfire, or acknowledging the expertise of a renowned shot, the theme of marksmanship is prevalent.
In conclusion, the correct option that describes Atticus Finch's shooting ability when dealing with the mad dog is that he is an expert shot. This is evidenced not only by the act itself but also by the admiring crowd's expectation of seeing a display of marksmanship, which further supports the conclusion that Atticus is indeed very skilled with a rifle.