With regard to the action of hormones and neurotransmitters on cellular receptors,which of these describes "amplification"?

A)When the extracellular concentration of a chemical messenger reaches a very high level,it overwhelms transporter molecules and the chemical floods into the cell.
B)Only hydrophilic first-messenger molecules can activate second-messenger molecules within the cell cytosol.
C)A single first-messenger molecule activates multiple second-messenger molecules,each of which activate thousands of enzymes.
D)Some cellular receptors have such low affinity for chemical ligands that it can require a million or more molecules to activate them.