Ori overhears his study partners discussing a feedback loop where Substance M is released, and the more Substance M is released the more is generated. They note that humans don't release Substance M all the time, only when the pathway is activated. What type of feedback loop is this and why?

• A. Negative feedback because it's the most common. 
• B. Negative feedback because the process is returning the body to the set point. 
• C. Positive feedback because the amount of the substance is increasing. 
• D. Positive feedback because the process increasingly moves away from the starting condition.