The irony is that they are smiling with “torn and bleeding hearts”.
The idea it emphasizes is that they are smiling to hide their pain.
The overall message revealed by the irony is that they are in considerable emotional turmoil and faking happiness to mask their distress.
The reason why the boy's father doesn't tell the boy to leave is : C. The father is unconsciousI think it's pretty much self-explanatory. No father will let danger come to his son if he can help it
Your tone
Let's look at the other choices first. Your credibility is your ability to be believed as trustworthy in regards to the subject. Whether you're talking to a group of teenagers or professional adults, your credibility doesn't change. Your clarity also should not change based on the audience because you want to be clear in your message at all times. Also, your purpose should be the same no matter the audience. The only thing that would change is your tone. The way you approach a crowd of teenagers would vary greatly from the way you'd approach a room of professionals.
The last one
Hope that helps ❤️️
The author twists the words and uses literary elements