Which organs/glands are important in regulating water output?

The water that leaves the body as exhaled air, sweat or urine is ultimately extracted from blood plasma and the organs/glands which are important in regulating water output are the kidneys, hypothalamus and endocrine glands. The kidney has a remarkable ability to dilute or concentrate urine according to an individual’s changing physiological needs and to regulate electrolyte excretion. Moreoever the hypothalamus is located in the brain and links the nervous and endocrine systems to each other. In addition, the endocrine glands secrete their porducts and hormones directly into the blood rather that through duct and the major glands of the endocrine system include hypothalamus. Endocrine glands secrete chemicals such as saliva or sweaat and secrete hormones directly into the blood stream. 

answer; /// i believe the correct answer is (thrombocytopenia); (a)

the answer to your question is b