Question: the type of cloud that is known for causing thunderstorms
[{'answer': 'cumulonimbus', 'provenance': [{'wikipedia_id': '70807', 'title': 'Thunderstorm', 'start_paragraph_id': 1, 'start_character': 312, 'end_paragraph_id': 1, 'end_character': 324, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '70807', 'title': 'Thunderstorm', 'start_paragraph_id': 1, 'start_character': 70, 'end_paragraph_id': 1, 'end_character': 1049, 'bleu_score': 0.8501106780934861, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 4057831035006666615}, 'section': 'Section::::Abstract.'}]}]