Sad, sprint, hop, scream, unusual, weep
The answer is the last one, D. All of the other transitions indicate that the writer will either go into further detail on the subject or list other reasons as to why this would be correct. However, D clearly uses a contrasting transition to introduce a new argument.
Answer:
1. When he threw the challenge to his neighbors to jump the tallest hedges.
2. His belief triumphed over the skills of his opponents
3. When he boasted in school that he will win the heavy weight championship.
Explanation:
Ali actually believed in himself. We see how he demonstrated and carried out his belief. He made it a public declaration that he is the greatest of all time in boxing.