Part A:
The best inference that can be made about Daniel's "midlife crisis" noted "affectionately" by his friends is:
C. Daniel is reflecting on the artistic goals and achievements of his youth and wants to feel that happiness again.
Part B:
The sentence from the text that BEST supports the answer in part A is:
C. Looking back at his teenage years when he'd spent so much of his time and energy creating works of art, he realized that he had been like a butterfly then, free and light and perfectly content.