This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Disorders of Parathyroid Gland, Subject name: Medicine
A middle aged female has a pathological fracture of clavicle and ribs. The X-ray shows periosteal resorption of 2nd and 3rd metatarsals and phalanges. Most probable cause is? 
Select and explain. 
A. Hyperparathyroidism, B. Hypoparathyroidism, C. Renal Osteodystrophy, D. Osteomalacia
A: Hyperparathyroidism
Answer: A: Hyperparathyroidism 
Explanation: The following clinical presentation is suggestive of Hyperparathyroidism The low production of vitamin D3 by kidney leads to low calcium The P.T.H levels rise to compensate for low serum calcium and result in bone resorption. The distinctive bone manifestation of hyperparathyroidism is osteitis fibrosa cystica X-ray changes include resorption of the phalangeal tufts and replacement of the sharp coical outline of the bone in the digits by an irregular outline (sub-periosteal resorption).