The correct option is B Vasopressin
Diabetes insipidus is a condition, in which one is always thirsty and excretes large amounts of diluted urine, with reduction of fluid intake having no effect on the concentration of urine. Due to deficiency of vasopressin or antidiuretic hormone, ADH production in the hypothalamus diabetes insipidus takes place.
Thus, the correct answer is the option (B), 'Vasopressin'.