Question: where does the highest rate of tubular reabsorption occur
[{'answer': 'proximal tubule', 'provenance': [{'wikipedia_id': '14786716', 'title': 'Renal sodium reabsorption', 'start_paragraph_id': 4, 'start_character': 45, 'end_paragraph_id': 4, 'end_character': 60, 'bleu_score': 1.0, 'section': 'Section::::Proximal tubule.\n'}]}]