Question: who signed the gun control act of 1968
[{'answer': 'President Lyndon B. Johnson', 'provenance': [{'wikipedia_id': '320600', 'title': 'Gun Control Act of 1968', 'start_paragraph_id': 2, 'start_character': 31, 'end_paragraph_id': 2, 'end_character': 58, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '320600', 'title': 'Gun Control Act of 1968', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 276, 'bleu_score': 0.9611463610973231, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 4945632212834546094}, 'section': 'Section::::Abstract.'}]}]