The correct option is
C Target cells
Hormones are chemicals or signaling molecules secreted from endocrine glands in the blood from where they are carried to target cells and cause changes in their functioning and regulation.
Hormones bind to specific proteins known as hormone receptors to produce their effects. These receptors are present on target cells only.
Receptors may be membrane-bound or intracellular depending upon whether they are present on the cell membrane or inside the cell.
So, the correct answer is 'Target cells'.