Final answer:
Dav Pilkey was most influenced by his experiences with his second grade teacher when creating "Captain Underpants," as his time in the hallway due to his behavior led to the creation of original characters.
Step-by-step explanation:
The creator of the "Captain Underpants" series, Dav Pilkey, was most influenced by C. His experience with his second grade teacher. Pilkey, who had dyslexia and ADHD, would often be reprimanded for his behavior in class, leading his teacher to frequently place him in the hallway, where he would create his own original comic book characters. It was during those times that his childhood experiences and imagination nurtured the idea for Captain Underpants, a character that would captivate and entertain young readers around the world. This suggests that while Pilkey certainly created books that children would enjoy (D), and despite any difficulties in listening or controversy his books may have later faced (A and B), it was his second-grade experiences that were the most formative in his journey as an author.