Question: when was ben and jerry's sold to unilever
[{'answer': 'April 2000', 'provenance': [{'wikipedia_id': '171275', 'title': "Ben & Jerry's", 'start_paragraph_id': 13, 'start_character': 3, 'end_paragraph_id': 13, 'end_character': 13, 'bleu_score': 1.0, 'section': 'Section::::History.:Unilever era.\n'}]}, {'provenance': [{'wikipedia_id': '171275', 'title': "Ben & Jerry's", 'start_paragraph_id': 13, 'start_character': 0, 'end_paragraph_id': 13, 'end_character': 389, 'bleu_score': 0.9318557434050331, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 6149573106181306478}, 'section': 'Section::::History.:Unilever era.\n'}]}]