I need help responding to the following answer:

To determine if a behavior is normal or abnormal, a person must first understand normal expectations. We can measure how a behavior compares to normal expectations by using the four D's as a guideline to evaluating the behavior. The four D's are deviance, dysfunction, distress, and danger. A clinal decision is made depending on the intensity, duration, and frequency of the behavior relative to the norm. The evaluation will also measure the level of concern as mild, moderate, or severe.

An example

Last school year, we had a kindergartener that refused to talk. She was bright and bubbly, but did not speak a single word. (Not really sure how a child can pass a grade without talking the entire year). But, it was an abnormal behavior. Normal behavior for a kindergartener is to talk and laugh and be excited to answer and bring attention to themselves. I think the student was expressing the D of distress. Something was triggering stressors that made her not want to talk. Not very often do you come across a student who will not talk to an adult and rarely to any of their classmates, and does not play at recess. Moving into first grade she did the same thing for the first few months, but somehow the teacher was able to get her to talk to her. She still does not talk to adults, only to her teacher.