All of the Following Are Examples of Amplification of a Hormone

All of the following are examples of amplification of a hormone signal EXCEPT

A) different cell types have different receptors capable of binding the same hormone.
B) 0.09 mg of growth hormone leads to a 10,000- mg weight gain in a cow.
C) epinephrine initiates an enzyme cascade.
D) steroids bind hormone- response elements in the cell and initiate gene transcription.