Question: who was the president of south africa in 1993
[{'answer': 'F.W. de Klerk', 'provenance': [{'wikipedia_id': '1561385', 'title': '1993 in South Africa', 'start_paragraph_id': 3, 'start_character': 29, 'end_paragraph_id': 3, 'end_character': 40, 'bleu_score': 1.0, 'section': 'Section::::Incumbents.\n'}]}, {'provenance': [{'wikipedia_id': '1561385', 'title': '1993 in South Africa', 'start_paragraph_id': 3, 'start_character': 0, 'end_paragraph_id': 3, 'end_character': 42, 'bleu_score': 0.6147881529512641, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 56817175861141524}, 'section': 'Section::::Incumbents.\n'}]}]