Step 1: Understanding multimolecular colloids.
Multimolecular colloids are those where the particles consist of aggregates of molecules, typically smaller than macromolecules. These particles can be made from small molecules or atoms.
Step 2: Analyzing the options.
(A) Silver sol: Correct — Silver sol is a colloidal solution where silver particles are dispersed in water and they form aggregates. This qualifies as a multimolecular colloid.
(B) Solution of rubber in organic solvent: This is a macromolecular colloid, not multimolecular.
(C) Aqueous solution of protein: This can be a macromolecular colloid, where proteins are large molecules and form colloidal solutions.
(D) Aqueous polyvinyl alcohol: This is a macromolecular colloid as well.
Step 3: Conclusion.
The correct answer is (A) Silver sol, as it is an example of a multimolecular colloid.