The component of a homeostatic control system which transmits the response is called the receptor.
The receptor is the part of the human body that experiences everything - if you hurt yourself, that receptor will transmit the pain signal throughout the body, reach the brain, which will then make you react to pain in one way or another.
Assuming a 10% trophic efficiency, the herbivore (primary consumer) will get 10% of the producer energy. Then, the second consumer that eat the herbivore will get 10% of the primary consumer energy, so it is 10%*10%= 1% of the primary producers.
Then, the t<span>ertiary consumer should get 0.1% of the primary producers' energy.</span>
Sounds like it could be C, but I don't have much context.
