Symptoms of ptsd include all of the following except
intrusive thoughts or memories of a traumatic event
avoidance of things that remind one of a traumatic event
jumpiness
physical complaints that cannot be explained medically

d. physical complaints that cannot be explained medically, is not a symptom of PTSD.

Explanation:

Posttraumatic stress disorder (PTSD) is a type of mental disorder which is caused by  exposure to a traumatic event. The traumatic event that can induce this disorder are traffic collisions, loss of loved one, sexual assault, natural disaster terrorism etc.

Some of the symptoms of the posttraumatic stress disorder include flashbacks of the traumatic event, recurring dreams, disturbing thoughts, irritability, avoiding things related to the event, detachment from others and jumpiness.    

Therefore, physical complaints that cannot be explained medically is not a symptom of PTSD.

the factors that the economies of the muslim empires prosper were:

1- land trade routes-located between three continents  

2- sea trade routes

trade contributed to the spread of muslim empires, and with that islamic culture led to a growing feeling of internationalism resulted in the transfer of technology, science, and other cultural forms.