Answer:
B). Hawaii,
Step-by-step explanation:
As per the question, the second option i.e. 'Hawaii,' most appropriately revises the underlined part of the sentence as it follows the punctuation rules correctly which makes it syntactically accurate. Since the sentence involves a colon(:) to introduce a list of details about the term, it would require a comma(,) after the first detail('the Ironman Triathlon held annually in Hawaii,') which is appropriately done in the second option. Thus, option B is the correct answer and final sentence reads as:
'Yet only one definition of the term truly lives up to its name: the Ironman Triathlon held annually in Hawaii, a picturesque setting for a challenging race.'