Question: what type of cells are primarily responsible for the secretion of intrinsic factor
[{'answer': 'Parietal cells', 'provenance': [{'wikipedia_id': '661769', 'title': 'Parietal cell', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 14, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '661769', 'title': 'Parietal cell', 'start_paragraph_id': 23, 'start_character': 0, 'end_paragraph_id': 23, 'end_character': 650, 'bleu_score': 0.9792717993254391, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 4223739703086008758}, 'section': 'Section::::Function.:Intrinsic factor secretion.\n'}]}]