Question: iron pillar near qutub minar built by whom
[{'answer': 'king Chandra', 'provenance': [{'wikipedia_id': '52631552', 'title': 'Iron pillar of Delhi', 'start_paragraph_id': 29, 'start_character': 157, 'end_paragraph_id': 29, 'end_character': 169, 'bleu_score': 1.0, 'section': 'Section::::Inscriptions.:Inscription of King Chandra.:Issuance.\n'}]}]