Answer:
Specific Cell-surface receptor
Step-by-step explanation:
Water-soluble hormone are not soluble in the plasma membrane therefore they can not cross the plasma membrane so they only binds to the cell surface receptor which has specific binding site for the hormone.
The water-soluble hormones comes majorly from amino acids which bind to the GPCR and activates the G protein which in turn activate adenylyl cyclase and a series of reaction gets triggered which alters the cell activity. Receptors for lipophilic hormone or ligands are present in the cytoplasm and nucleus.
Therefore the correct answer is a specific cell surface receptor.