Answer

B: Colloid

Why?

Here is my explanation:

It behaves like a colloidal suspension, although cement particles are much coarser than conventional colloid size. The origins of this colloidal behaviour of a cement paste have been traced to high density and high viscosity of the paste itself.

Concrete is a heterogeneous mixture. It is composed of cement, water, and aggregate that can be crushed stone, sand, and/or gravel.

Hope this helps.. :)