Question: what is the highest rank in the marine corps
[{'answer': 'General', 'provenance': [{'wikipedia_id': '6738858', 'title': 'United States Marine Corps rank insignia', 'start_paragraph_id': 2, 'start_character': 394, 'end_paragraph_id': 2, 'end_character': 401, 'bleu_score': 1.0, 'section': 'Section::::Commissioned officers.\n'}]}]