Which of the following drugs produces dissociative anesthesia

The anesthetized state has been termed dissociative anesthesia because patients who receive ketamine alone appear to be in a cataleptic state, in contrast to other states of anesthesia that resemble normal sleep. Patients anesthetized with ketamine have profound analgesia, but they keep their eyes open and maintain many reflexes. Corneal, cough, and swallow reflexes all may be present, but they should not be assumed to be protective. The patient has no recall of surgery or anesthesia, but amnesia is not as prominent with ketamine as with the benzodiazepines. Ref: Miller's anesthesia 8th edition