Which of the following serves as a sensor, or as part of a sensor, that functions only in a negative feedback system and not in a positive feedback system?
A. CaSRs (Calcium-Sensing Receptors) located only in the nucleus of Parathyroid Gland cells.
B. Parathryroid Hormone Receptors (PTHRs) located only in the plasma membranes of Parathyroid Gland cells.
C. Force-gated (mechanically-gated) channels in the plasma membranes of mechanoreceptor (force-sensitive) neurons located in the walls of the uterus of a pregnant female.