Here's a problem to solve: In a series of chemical reactions, X→Y→Z→A, X converts to Y, Y converts to Z, and Z converts to A. Which term describes the process if the production of A interferes with the conversion of X to Y?

Among the 4 following options, which is the correct answer?

- A: a complimentary response
 
- B: a control system
 
- C: negative feedback
 
- D: positive feedback
 