Question: who has shortest tenure as governor of rbi
[{'answer': 'Amitav Ghosh', 'provenance': [{'wikipedia_id': '1893658', 'title': 'List of governors of the Reserve Bank of India', 'start_paragraph_id': 2, 'start_character': 209, 'end_paragraph_id': 2, 'end_character': 221, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]