Answer:
The interview question that shows understanding of the significance of the event is B. "Who was with you on that exhilarating day on the mountain?"
This question acknowledges the importance of the event by using the adjective "exhilarating" to describe it, indicating that it was a notable and significant experience. Additionally, it specifically asks about the people who were with the person during the event, implying that they played a role in the significance of the event. This question shows an understanding of the event's impact and the significance of the people involved, indicating a deeper understanding of the event being discussed.