Question: what crop was known as virginia's gold and silver
[{'answer': 'tobacco', 'provenance': [{'wikipedia_id': '22416349', 'title': 'History of Jamestown, Virginia (1607–99)', 'start_paragraph_id': 59, 'start_character': 677, 'end_paragraph_id': 59, 'end_character': 684, 'bleu_score': 1.0, 'section': 'Section::::The Starving Time.:Lord De La Warr.\n'}]}, {'provenance': [{'wikipedia_id': '22416349', 'title': 'History of Jamestown, Virginia (1607–99)', 'start_paragraph_id': 67, 'start_character': 0, 'end_paragraph_id': 67, 'end_character': 566, 'bleu_score': 0.978138775770484, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 12988996407227414065}, 'section': 'Section::::Expansion beyond Jamestown.:Tobacco.\n'}]}]