Question: how many episodes of season 5 of vikings
[{'answer': '10', 'provenance': [{'wikipedia_id': '49829845', 'title': 'Vikings (season 5)', 'start_paragraph_id': 91, 'start_character': 109, 'end_paragraph_id': 91, 'end_character': 111, 'bleu_score': 1.0, 'section': 'Section::::Reception.:Critical response.\n'}]}]