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
Hyponatremia may be seen in all of the following conditions except - 
Select and explain. 
A. Mucoviscidosis, B. SIADH, C. Diabetes insipidus, D. Adrenal hyperplasia
C: Diabetes insipidus
Answer: C: Diabetes insipidus 
Explanation: Vasopressin, secreted from posterior pituitary, is the principal regulator of tonicity,with its release largely stimulated by increase in plasma tonicity. Diabetes insipidus manifests clinically with polyuria and polydypsia and can result from either vasopressin deficiency or vasopressin insensitivity at the level of kidney.As a result, hypernatremia occurs. Page 1881 & 1882, Nelson textbook of pediatrics 19th edition