Question: who is the host of season 4 spring baking championship
[{'answer': 'Ali Khan', 'provenance': [{'wikipedia_id': '51841355', 'title': 'Spring Baking Championship', 'start_paragraph_id': 2, 'start_character': 310, 'end_paragraph_id': 2, 'end_character': 318, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '51841355', 'title': 'Spring Baking Championship', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 343, 'bleu_score': 0.9663744727315161, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 14389773329124089188}, 'section': 'Section::::Abstract.'}]}]