Answer:
The correct answer is - dissociative.
Explanation:
Acute stress disorder is a mental condition that is characterized by the increasing development of a serious dissociation, anxiety and many other symptoms such as depression, behavioral change and many other that takes place after a traumatic incident such as death, accident or similar cases.
In this case Kat is exhibiting dissociation symptom of the acute stress disorder as she is not remembering her colleagues and students after very little of the mass shooting at her school.
Thus, the correct answer is - dissociative.