The correct option is C When there is a decrease in the blood pressure.
Secreted by the juxtaglomerular cells, renin (not to be confused with rennin, the digestive enzyme) is also known as angiotensinogen. It is an enzyme and not a hormone. It helps regulate the body's mean arterial pressure. It is secreted in response to a decrease in blood pressure. It causes a cascade of events ultimately leading to an increase in blood pressure.