Final answer:
Harper Lee based the character of Dill in 'To Kill a Mockingbird' on childhood friend Truman Capote, not Ernest Hemingway. Capote's creative and charismatic personality inspired the character.
Step-by-step explanation:
Harper Lee based the character Dill in her novel To Kill a Mockingbird on her own childhood friend, Truman Capote. Dill is a creative and charismatic character, much like Capote himself. Despite Ernest Hemingway's strong reputation as a writer, he was not the inspiration for the character of Dill. Instead, it was Truman Capote, known for works such as In Cold Blood and Breakfast at Tiffany's, who influenced the creation of Dill. Therefore, the correct answer to the question "On what writer did Harper Lee base Dill?" is (D) Truman Capote.