Question: who plays joffrey's mother in game of thrones
[{'answer': 'Lena Headey', 'provenance': [{'wikipedia_id': '28059680', 'title': 'List of Game of Thrones characters', 'start_paragraph_id': 162, 'start_character': 30, 'end_paragraph_id': 162, 'end_character': 41, 'bleu_score': 1.0, 'section': 'Section::::Main characters.:Cersei Lannister.\n'}]}]