Question: who has the most career grand slams in mlb history
[{'answer': 'Alex Rodriguez', 'provenance': [{'wikipedia_id': '2989618', 'title': 'Grand slam (baseball)', 'start_paragraph_id': 4, 'start_character': 0, 'end_paragraph_id': 4, 'end_character': 14, 'bleu_score': 1.0, 'section': 'Section::::Notable highlights.\n'}]}]