Answer:
A .colloid
Step-by-step explanation:
The laser beam is visible because it is scattered by the particle in the mixture. This scattering of light is called Tyndall effect.
In a solution, the particle size is too small so its scattering ability is very low. If the laser shines through a solution it will not be viable inside the solution.
In a suspension the particle size is too large and they will scatter the light very much. so the light will be visible only for a small portion of the beaker. The beam will not be clear since the bigger particles create shadows. The beam will not be narrow. The entry point will be visible but not the exit point
In a colloid, the particle size is neither too small not too big and it will not deposit at the bottom of the container. When a laser pointer shines through a colloid a clear uniform and narrow beam will be observed. Both the entry point and the exit point will be visible.