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
Activation of the renin stimulates - 
Select and explain. 
A. Water excretion, B. Potassium retention, C. Sodium retention, D. Magnesium excretion
C: Sodium retention
Answer: C: Sodium retention 
Explanation: increase secretion of renin causes sodium retention, potassium excretion, increase ECF volume, magnesium retention ( Harrison 17 pg 2251)