Question: who is the guru of karan in mahabharat
[{'answer': 'Parashurama', 'provenance': [{'wikipedia_id': '857051', 'title': 'Karna', 'start_paragraph_id': 22, 'start_character': 115, 'end_paragraph_id': 22, 'end_character': 126, 'bleu_score': 1.0, 'section': 'Section::::Biography.:Birth and childhood.\n'}]}]