The combination of states that best represents Tornado Alley is:
c) Oklahoma, Kansas, Nebraska
Tornado Alley is a region in the central United States known for its frequent and intense tornado activity. It includes parts of Oklahoma, Kansas, Nebraska, as well as portions of Texas, South Dakota, North Dakota, Iowa, and sometimes extends into Colorado and Minnesota. The states mentioned in option c are at the core of Tornado Alley and experience a high frequency of tornadoes.