Answer: A. Watching him bravely tell the truth about what had really happened that day and how he had been the one responsible for the destruction of our neighbor’s award-winning flower garden, I realized that he knew he would likely face unpleasant consequences.
Explanation: in the sentence 2, Kara's says that what her brother did that day was very difficult for him, referring to a time when her brother told the truth about something he had done, even though if he lied, he would avoided the punishment, the option A is the one that make that sentence more precise, by explaining the events that led him to tell the truth despite the consequences.