Question: who plays stef's mother on the fosters
[{'answer': 'Annie Potts', 'provenance': [{'wikipedia_id': '44557120', 'title': 'List of The Fosters characters', 'start_paragraph_id': 38, 'start_character': 12, 'end_paragraph_id': 38, 'end_character': 23, 'bleu_score': 1.0, 'section': 'Section::::Recurring and minor characters.:Characters.\n'}]}]