Question: what is the active ingredient in vicks vapor rub
[{'answer': 'Camphor ( synthetic )'}, {'answer': 'Eucalyptus oil'}, {'answer': 'Menthol', 'provenance': [{'wikipedia_id': '8350109', 'title': 'Vicks VapoRub', 'start_paragraph_id': 1, 'start_character': 28, 'end_paragraph_id': 1, 'end_character': 35, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]