Question: who became a leading speaker against slavery and publisher of an antislavery newspaper
[{'answer': 'Frederick Douglass', 'provenance': [{'wikipedia_id': '3498684', 'title': 'The North Star (anti-slavery newspaper)', 'start_paragraph_id': 1, 'start_character': 137, 'end_paragraph_id': 1, 'end_character': 155, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '3498684', 'title': 'The North Star (anti-slavery newspaper)', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 500, 'bleu_score': 0.9483044717870771, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 10291531589665549292}, 'section': 'Section::::Abstract.'}]}]