Answer: The correct answer is colloid.
Step-by-step explanation:
The solutions are classified into 3 types on the basis of size of the particles.
1.) Solution: When the size of the particles is between 0.1 nm to 1 nm, then the solution is considered to be as a true solution.
2,) Colloid: When the size of the particles is between 2 to 1000 nm, then the solution is considered to be as a colloid.
3.) Suspension: When the size of the particles is greater than 1000 nm, then the solution is considered to be as a suspension.
When soap is shaken in water, the soap particles gets suspended in the solution and does not settle down. The particle size is intermediate and remain in the solution. The particles can be distinguished by bare eyes.
Hence, the correct answer is colloid.