Question: An American twin-engine attack helicopter that was developed for the United States Marine Corps as part of the H-1 upgrade program is also called what when based on the ICAO phonetic alphabet pronunciation of it's variant letter?
{'answer': 'Zulu Cobra', 'supporting_facts': [['Bell AH-1Z Viper', 0], ['Bell AH-1Z Viper', 2], ['NATO phonetic alphabet', 0]]}