This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Medicine
Increased Ca, decreased P04.Diagnosi- 
Select and explain. 
A. Primary hyperparathyroidism, B. Secondary hyperparathyroidism due to Vit D deficiency, C. Malignancy, D. Osteoporosis
A: Primary hyperparathyroidism
Answer: A: Primary hyperparathyroidism 
Explanation: Lab Diagnosis of primary hyperparathyroidism(Figs 9.18 to 9.21) a.Biochemical 1.Simultaneous parathormone and calcium level should be taken 2.Parathormone level is increased 3.Increased calcium (more than 12 mg%), and chloride 4.Decreased phosphorus, potassium and bicarbonate 5.Serum chloride/phosphorus ratio is diagnostic more than 75% (normal < 32%) b.Urinary calcium excretion is increased c.ECG--Sho QT interval d.Localisation by USG, CT, MRI, nuclear thallium technetium scan and parathyroid angiography (Figs 9.20 and 9.21).e.Radiological findings in hyperparathyroidism include osteitis fibrosa cystica, subperiosteal erosion especially along the radial aspect of middle phalanx, pepper pot skull (Fig. 9.19). R ALAGAPPAN MANUAL OF PRACTICAL MEDICINE FOUH EDITION PAGE NO-630