Question: who determined the mass of the electron (points 3)
[{'answer': 'J.J. Thomson', 'provenance': [{'wikipedia_id': '902', 'title': 'Atom', 'start_paragraph_id': 15, 'start_character': 14, 'end_paragraph_id': 15, 'end_character': 26, 'bleu_score': 1.0, 'section': 'Section::::History of atomic theory.:Discovery of the electron.\n'}]}, {'provenance': [{'wikipedia_id': '902', 'title': 'Atom', 'start_paragraph_id': 15, 'start_character': 0, 'end_paragraph_id': 15, 'end_character': 1017, 'bleu_score': 0.9873810715615521, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 15123517802642999300}, 'section': 'Section::::History of atomic theory.:Discovery of the electron.\n'}]}]