Question: who did serena williams beat in the olympics
[{'answer': 'Maria Sharapova', 'provenance': [{'wikipedia_id': '35841026', 'title': '2012 Serena Williams tennis season', 'start_paragraph_id': 16, 'start_character': 658, 'end_paragraph_id': 16, 'end_character': 673, 'bleu_score': 1.0, 'section': 'Section::::Year in detail.:Clay court season and French Open.:Mutua Madrid Open.\n'}]}, {'answer': 'Victoria Azarenka', 'provenance': [{'wikipedia_id': '35841026', 'title': '2012 Serena Williams tennis season', 'start_paragraph_id': 16, 'start_character': 1038, 'end_paragraph_id': 16, 'end_character': 1055, 'bleu_score': 1.0, 'section': 'Section::::Year in detail.:Clay court season and French Open.:Mutua Madrid Open.\n'}]}, {'answer': 'Caroline Wozniacki', 'provenance': [{'wikipedia_id': '35841026', 'title': '2012 Serena Williams tennis season', 'start_paragraph_id': 11, 'start_character': 738, 'end_paragraph_id': 11, 'end_character': 756, 'bleu_score': 1.0, 'section': 'Section::::Year in detail.:Early hard court season and Australian Open.:Sony Ericsson Open.\n'}]}, {'answer': 'Vera Zvonareva', 'provenance': [{'wikipedia_id': '35841026', 'title': '2012 Serena Williams tennis season', 'start_paragraph_id': 28, 'start_character': 609, 'end_paragraph_id': 28, 'end_character': 623, 'bleu_score': 1.0, 'section': 'Section::::Year in detail.:Grass court season: Wimbledon Championships and the Olympics.:London Olympics.\n'}]}, {'answer': 'Urszula Radwańska', 'provenance': [{'wikipedia_id': '35841026', 'title': '2012 Serena Williams tennis season', 'start_paragraph_id': 28, 'start_character': 313, 'end_paragraph_id': 28, 'end_character': 330, 'bleu_score': 1.0, 'section': 'Section::::Year in detail.:Grass court season: Wimbledon Championships and the Olympics.:London Olympics.\n'}]}, {'answer': 'Jelena Janković', 'provenance': [{'wikipedia_id': '35841026', 'title': '2012 Serena Williams tennis season', 'start_paragraph_id': 28, 'start_character': 167, 'end_paragraph_id': 28, 'end_character': 182, 'bleu_score': 1.0, 'section': 'Section::::Year in detail.:Grass court season: Wimbledon Championships and the Olympics.:London Olympics.\n'}]}, {'provenance': [{'wikipedia_id': '35841026', 'title': '2012 Serena Williams tennis season', 'start_paragraph_id': 28, 'start_character': 0, 'end_paragraph_id': 28, 'end_character': 1929, 'bleu_score': 0.9810054000078321, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17314939853150254863}, 'section': 'Section::::Year in detail.:Grass court season: Wimbledon Championships and the Olympics.:London Olympics.\n'}]}]