Part A:
The most likely purpose of the author for writing the letter in “You Are the Electric Boogaloo” is A. to show compassion for his younger self. The tone of the letter suggests a sense of empathy and understanding towards the author's past experiences, rather than outright trying to persuade or guide his younger self in a specific direction.
Part B:
The quotation that best supports the answer to Part A is D. Just go to sleep, kid, and get ready for the next dance. It’s all going to be great, okay? This line conveys a sense of reassurance and comfort, indicating a compassionate approach towards the author's younger self, encouraging optimism and understanding.