Question: what type of rocks form when lava cools after a volcanic eruption
[{'answer': 'Volcanic rock', 'provenance': [{'wikipedia_id': '316414', 'title': 'Volcanic rock', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 13, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '316414', 'title': 'Volcanic rock', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 642, 'bleu_score': 0.955468993395951, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10655722416096233979}, 'section': 'Section::::Abstract.'}]}]