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
Which of the following is associated with elevated alkaline phosphate, low calcium with low phosphate? 
Select and explain. 
A. Paget's disease, B. Osteoporosis, C. Primary hyperparathyroidism, D. Vitamin D deficiency
D: Vitamin D deficiency
Answer: D: Vitamin D deficiency 
Explanation: Option A - Paget's disease: Normal Ca+, Normal PO4, SAP |||| Option B - Osteoporosis: Normal Ca+, Normal PO4, SAP normal Option C - Primary Hyperparathyroidism | Ca+, | PO4, SAP |, Bone turnover| Option D - Vitamin D deficiency: Calcium | , PTH| , PO4| , SAP | Note: Ca+ is inversely propoional to PO4