Answer:
The correct option is: C. Incidence
Step-by-step explanation:
Incidence refers to the probability of new instances or occurrence of injuries, diseases, disorders or medical conditions in a given population over a specific period of time.
The rate of incidence can also be described as the rate of occurrence or frequency of the new medical cases over a specific time period.
Therefore, Incidence can be used to describe the newly diagnosed cases of posttraumatic stress disorder after the tornado.