Question: how many dolphins are born at a time
[{'answer': 'a single calf', 'provenance': [{'wikipedia_id': '9061', 'title': 'Dolphin', 'start_paragraph_id': 122, 'start_character': 389, 'end_paragraph_id': 122, 'end_character': 402, 'bleu_score': 1.0, 'section': 'Section::::Behavior.:Reproduction and sexuality.\n'}]}, {'provenance': [{'wikipedia_id': '9061', 'title': 'Dolphin', 'start_paragraph_id': 122, 'start_character': 0, 'end_paragraph_id': 122, 'end_character': 617, 'bleu_score': 0.9806740509884301, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 6716722505124193344}, 'section': 'Section::::Behavior.:Reproduction and sexuality.\n'}]}]