Step 1: Understanding the Concept
Solubility of a solid in a liquid depends on the nature of the solute, the nature of the solvent and the temperature.
Step 2: Role of pressure
Both solid and liquid phases are nearly incompressible, so pressure changes do not change the solubility noticeably.
Step 3: Contrast
Pressure matters for gases dissolved in liquids (Henry's law), but not here.
Final Answer:
Solubility of a solid in a liquid does not depend on pressure.
\[ \boxed{\text{(C) }\text{Pressure}} \]