Question: ratio of masses of proton and electron is
[{'answer': 'μ', 'provenance': [{'wikipedia_id': '18521875', 'title': 'Proton-to-electron mass ratio', 'start_paragraph_id': 1, 'start_character': 47, 'end_paragraph_id': 1, 'end_character': 48, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'β', 'provenance': [{'wikipedia_id': '18521875', 'title': 'Proton-to-electron mass ratio', 'start_paragraph_id': 1, 'start_character': 52, 'end_paragraph_id': 1, 'end_character': 53, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'answer': 'proton - to - electron mass ratio'}, {'provenance': [{'wikipedia_id': '18521875', 'title': 'Proton-to-electron mass ratio', 'start_paragraph_id': 1, 'start_character': 3, 'end_paragraph_id': 1, 'end_character': 393, 'bleu_score': 0.800597213769159, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 5964248548560787823}, 'section': 'Section::::Abstract.'}]}]