<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 70-year-old woman presents to the office for a yearly physical. She states she has recently started experiencing pain in her legs and her back. Last year, she experienced a fracture of her left arm while trying to lift groceries. The patient states that she does not consume any dairy and does not go outside often because of the pain in her legs and back. Of note, she takes carbamazepine for seizures. On exam, her vitals are within normal limits. You suspect the patient might have osteomalacia. Testing for which of the following is the next best step to confirm your suspicion?? A: 7-dehydrocholesterol, B: 25-hydroxyvitamin D, C: 1,25-hydroxyvitamin D, D: Pre-vitamin D3, E: Dietary vitamin D2,  <response>: This is a patient with suspected osteomalacia based on her history of fracture, leg and back pain, lack of sun exposure and dairy consumption, and use of carbamazepine which can interfere with vitamin D metabolism. Osteomalacia is caused by inadequate mineralization of bone due to vitamin D deficiency. The best next test would be to check one of the vitamin D metabolites to confirm vitamin D deficiency. 25-hydroxyvitamin D is the major circulating form of vitamin D and reflects overall vitamin D status from both sunlight exposure and dietary intake. 1,25-dihydroxyvitamin D is the active form but levels may be normal or even elevated in early vitamin D deficiency due to secondary hyperparathyroidism. The other answer choices do not directly reflect vitamin D status.B: 25-hydroxyvitamin D 