Question: who discovered the electron using a cathod ray
[{'answer': 'J.J. Thomson'}, {'provenance': [{'wikipedia_id': '6943', 'title': 'Cathode ray', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 822, 'bleu_score': 0.8348866664720971, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 551392983930798990}, 'section': 'Section::::Abstract.'}]}]