Question: what is the main source of energy in the uk
[{'answer': 'Gas', 'provenance': [{'wikipedia_id': '5213545', 'title': 'Energy in the United Kingdom', 'start_paragraph_id': 11, 'start_character': 151, 'end_paragraph_id': 11, 'end_character': 154, 'bleu_score': 1.0, 'section': 'Section::::Energy sources.:Natural gas.\n'}]}]