Question: what is the highest base on the ph scale
[{'answer': 'greater than 14', 'provenance': [{'wikipedia_id': '24530', 'title': 'PH', 'start_paragraph_id': 2, 'start_character': 543, 'end_paragraph_id': 2, 'end_character': 558, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '24530', 'title': 'PH', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 580, 'bleu_score': 0.574417293430389, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8797750061016393583}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '24530', 'title': 'PH', 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 0, 'bleu_score': 1.0, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 8797750061016393583}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '24530', 'title': 'PH', 'section': 'Section::::Abstract.', 'start_paragraph_id': 2, 'end_paragraph_id': 2, 'meta': {'evidence_span': ['The neutral value of the pH depends on the temperature, being lower than 7 if the temperature increases. The pH value can be less than 0 for very strong acids, or greater than 14 for very strong b', 'The pH value can be less than 0 for very strong acids, or greater than 14 for very strong bases.']}}]}]