Question: when did west brom win the fa cup
[{'answer': '18 May 1968', 'provenance': [{'wikipedia_id': '9173767', 'title': '1968 FA Cup Final', 'start_paragraph_id': 1, 'start_character': 73, 'end_paragraph_id': 1, 'end_character': 84, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}]