Explanation

Colloidal particles have sizes that are larger than individual molecules found in true solutions but smaller than the particles in suspensions. This puts colloidal particles in an intermediate size range between true solutions and suspensions. In true solutions, the solute particles are individual molecules or ions that are uniformly dispersed and are typically on the order of nanometers (10^-9 meters) or smaller in size. In suspensions, the particles are larger and can be seen with the naked eye. Colloidal particles fall in between these two extremes, ranging in size from about 1 nanometer to 1000 nanometers (1 micrometer). So, colloidal particles are neither as small as true solution particles nor as large as suspension particles, making option C the correct answer.