Question: when do restricted free agents have to sign
[{'answer': 'December 1', 'provenance': [{'wikipedia_id': '9641900', 'title': 'Restricted free agent', 'start_paragraph_id': 19, 'start_character': 47, 'end_paragraph_id': 19, 'end_character': 57, 'bleu_score': 1.0, 'section': 'Section::::NHL.:Qualifying offers.\n'}]}]