Question: who signed into law the expansion of the medicare prescription benefit
[{'answer': 'President George W. Bush', 'provenance': [{'wikipedia_id': '378922', 'title': 'Medicare Prescription Drug, Improvement, and Modernization Act', 'start_paragraph_id': 2, 'start_character': 22, 'end_paragraph_id': 2, 'end_character': 46, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '378922', 'title': 'Medicare Prescription Drug, Improvement, and Modernization Act', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 111, 'bleu_score': 0.9067110266941041, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 5203533808175629784}, 'section': 'Section::::Abstract.'}]}]