Amixture has particles that cannot be seen but do reflect light
it should be classified as a
homogeneous mixture
suspension
solution
colloid

The correct answer among the choices given is the last option. A mixture has particles that cannot be seen but do reflect light. It should be classified as a colloid.  A colloid is a mixture in which one substance is suspended throughout another substance.

A solid

With solids the particles are very close together making the substance very dense, and because the particles are so close they don't have very much room to move, making the particle motion very low.