Step 1: Understanding the Concept
An amalgam is a solution of mercury in another metal, for example sodium amalgam.
Step 2: Identify solute and solvent
The solid metal is the larger component and acts as the solvent. Mercury is a liquid at room temperature and is the dissolved component, the solute.
Step 3: Compare the options
The solute is a liquid and the solvent is a solid.
Final Answer:
An amalgam is a solution of a liquid solute in a solid solvent.
\[ \boxed{\text{(C) }\text{liquid in solid}} \]