This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Musculoskeletal  disorders, Subject name: Pediatrics
Juvenile idiopathic ahriis includes all except: 
Select and explain. 
A. Psoriatic ahritis, B. Enthesis-related ahritis, C. Systemic ahritis, D. Reactive ahritis
D: Reactive ahritis
Answer: D: Reactive ahritis 
Explanation: Reactive ahritis is not included in Juvenile Idiopathic ahritis: Classification of Juvenile Idiopathic ahritis (JIA) Oligoahritis (4 or lesser joints) (Most common type) Polyahritis (5 or more joints) Systemic JIA Psoriatic ahritis Enthesis-related ahritis Ref: Nelson textbook of pediatrics 21st edition Pgno: 1259