This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
Category of patients with juvenile idiopathic ahritis, with HLA B27 positive in most of the cases, who present with entheisits, lower limb ahritis involving knees and ankle and presence of inflammatory low back pain, is most likely to be 
Select and explain. 
A. Enthesitis related ahritis, B. Rheumatoid ahritis, C. Reactive ahritis, D. Cryoglobulinemia
A: Enthesitis related ahritis
Answer: A: Enthesitis related ahritis 
Explanation: Answer- A. Enthesitis related ahritisAhritis most commonly affects the lower extremities, knees and ankles, but the hip can also be affected.Enthesitis occurs frequently and is commonly seen as plantar fasciitis, achiles tendinitis and patellar tendon enthesitis.Inflammatory back pain is often seen, defined as lumbosacral spinal pain at rest, with morning stiftress that improves on movement.There is a strong association with HLA B27,with most of the patients of enthesitis associated ahritis positive for HLA B27.Iritis, usually acute, severe hip disease.