The closest significance of “Halloween and hardware” in the passage is C. Harrison has been able to take his handicaps and make them more advantageous to him.
This refers to the use of hints to give a better understanding of a given text.
Hence, we can see that context clues were used in the given description of Harrison and how he had managed his handicaps as "nobody had ever born heavier handicaps" which shows that he was able to take his handicaps and make them more advantageous to him.
Read more about context clues here:
https://brainly.com/question/11247029