Question: which plate borders the south american plate on the east
[{'answer': 'African Plate', 'provenance': [{'wikipedia_id': '494322', 'title': 'South American Plate', 'start_paragraph_id': 1, 'start_character': 180, 'end_paragraph_id': 1, 'end_character': 193, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '494322', 'title': 'South American Plate', 'start_paragraph_id': 2, 'start_character': 13, 'end_paragraph_id': 2, 'end_character': 545, 'bleu_score': 0.6406364357446901, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 6575662664959338948}, 'section': 'Section::::Abstract.'}]}]