Question: when is season finale of this is us season 2
[{'answer': 'March 13 , 2018', 'provenance': [{'wikipedia_id': '55143891', 'title': 'This Is Us (season 2)', 'start_paragraph_id': 57, 'start_character': 45, 'end_paragraph_id': 57, 'end_character': 60, 'bleu_score': 1.0, 'section': 'Section::::Release.:Broadcast.\n'}]}, {'provenance': [{'wikipedia_id': '55143891', 'title': 'This Is Us (season 2)', 'start_paragraph_id': 3, 'start_character': 0, 'end_paragraph_id': 3, 'end_character': 227, 'bleu_score': 0.9517713210466091, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 7628042887165322820}, 'section': 'Section::::Abstract.'}]}]