Which psychologist can be described as working from a trance state theory of hypnosis?

Which psychologist can be described as working from a trance state theory of hypnosis?
 
  a. Dr. Amin says, Hypnosis is a social interaction between a hypnotist and a subject..
  b. Dr. Birnbaum says, Hypnosis is an altered state of awareness characterized by heightened suggestibility..
  c. Dr. Chestnut says, Hypnosis involves a splitting of consciousness..
  d. Dr. Davison says, In hypnosis, part of the subject's consciousness remains a hidden observer..
  e. Dr. Evans says, Hypnosis involves an altered state of awareness characterized by heightened suggestibility..