This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology and Rheumatology, Subject name: Medicine
A 67-year-old woman develops symptoms of cough and sputum production after an upper respiratory tract infection. A CXR does not show any signs of pneumonia but the report mentions a "pseudo fracture" sign (Looser zones) seen in the left scapula compatible with osteomalacia. She has no pain in the scapula. Which of the following best differentiates rickets and osteomalacia? 
Select and explain. 
A. the mineralization defect is less severe in osteomalacia, B. Osteomalacia is only produced by vitamin D deficiency, unlike rickets, C. the skeleton is at a different stage when affected, D. parathyroid hormone levels are only routinely elevated in rickets
C: the skeleton is at a different stage when affected
Answer: C: the skeleton is at a different stage when affected 
Explanation: Both rickets and osteomalacia are disorders in which mineralization of the organic matrix of the skeleton is defective. Rickets is the name when this disorder occurs in a growing skeleton, whereas osteomalacia occurs after the epiphyseal plates are closed.