Final answer:
The plot of a story, including conflicts and challenges, serves to reveal the main character's traits and growth. The anecdote from Mark Twain shows this development through the experiences and dialogue of the main character, aligning with the theme of trusting knowledge and training.
Step-by-step explanation:
The plot of a story plays a critical role in developing the main character by presenting challenges and conflicts that reveal their traits, motivations, and growth. Taking the example of Mark Twain's anecdote, the plot involving the challenge of navigating a riverboat helps us understand Twain's journey from confidence to self-doubt under pressure. The encounters he has, including the dialogue with Mr. Bixby and the added tension of observers, demonstrate his reliance on knowledge and training over second-guessing, aligning with the theme that knowledge and training should be trusted.
When it comes to the specific options provided, the engineer's order to the other men sheds light on his character as cold and practical. This reflects his professional decision-making in a crisis, which could imply a focus on efficiency and the greater good, even if it seems devoid of empathy. This action helps the reader understand the engineer's character under stressful situations.