Question: when was the grenfell tower in london built
[{'answer': '1974', 'provenance': [{'wikipedia_id': '54298175', 'title': 'Grenfell Tower', 'start_paragraph_id': 1, 'start_character': 200, 'end_paragraph_id': 1, 'end_character': 204, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '54298175', 'title': 'Grenfell Tower', 'start_paragraph_id': 1, 'start_character': 31, 'end_paragraph_id': 1, 'end_character': 403, 'bleu_score': 0.6571395451324901, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17340309217297621611}, 'section': 'Section::::Abstract.'}]}]