Question: how long is prime minister term in canada
[{'answer': "At Her Majesty 's pleasure", 'provenance': [{'wikipedia_id': '24135', 'title': 'Prime Minister of Canada', 'start_paragraph_id': 13, 'start_character': 35, 'end_paragraph_id': 13, 'end_character': 60, 'bleu_score': 0.668740304976422, 'section': 'Section::::Term of office.\n'}]}]