An 8-day old breast-fed baby presents with vomiting,poor feeding and loose stools.On examination the heart rate is 190/minute,blood pressure 50/30 mmHg,respiratory rate 72 breaths / minute and capillary refill time of 4 seconds.Investigations show hemoglobin level of 15 g/dl.Na 120 mEq/l,K 6.8 mEq/l,Cl 81 meq/l,bicarbonate 15 mEq/l,urea 30 mg/dl and creatinine 0.6 mg/dl.The most likely diagnosis is:

• A. Congenital adrenal hyperplasia
• B. Acute tubular necrosis
• C. Congenital hypertrophic pyloric stenosis
• D. Galactosemia