The correct answer is receptors
The sensitivity of the hormone is reduced by the prolonged exposure to receptors and gets down regulated.
The effect of a hormone on a target cell may be decreased by the presence of Receptors
Hormones mediate changes in garget cells by attaching to explicit hormone receptors. Along these lines, despite the fact that hormones circle all through the body and come into contact with a wide range of cell types, they just influence cells that have the fundamental receptors.
Receptors for a particular hormone might be found on various cells or might be restricted to few specific cells. Cells can have numerous receptors for a similar hormone yet regularly likewise have receptors for various kinds of hormones.
The quantity of receptors that react to a hormone decides the cell's affectability to that hormone, and the subsequent cell reaction.
i might be wrong but i think its a. let me know if i’m right and have a good rest of your day!