Final answer:
The type of receptor that binds to hydrophilic ligands is the cell-surface receptor found in the plasma membrane. The correct answer to the question is C) Plasma Membrane.
Step-by-step explanation:
There are two main types of receptors: internal receptors and cell-surface receptors. The type of receptor that binds to hydrophilic (bipolar) ligands is the cell-surface receptor, which is located in the plasma membrane. These receptors cannot traverse the hydrophobic core of the plasma membrane, thus they bind to their ligands outside the cell and initiate a signaling cascade that transmits the signal inside the cell. In contrast, internal receptors, which are located inside the cell, typically bind to hydrophobic ligands that can easily cross the plasma membrane.
Therefore, the correct answer to the question is that the receptor located in the plasma membrane binds to hydrophilic ligands. Hence, the appropriate fill in the blanks from the provided options would be: C) Plasma Membrane.