Homogeneous Mixture: A homogeneous mixture is a type of mixture that is uniform in composition throughout. This means that the components of the mixture are evenly distributed and cannot be easily distinguished.

Among the given options, a dilute solution of alcohol in water (option C) is a homogeneous mixture. Let's understand why.

Dilute Solution of Alcohol in Water:
- A solution is a homogeneous mixture where one substance (solute) is dissolved in another substance (solvent). In this case, alcohol is the solute and water is the solvent.
- When alcohol is added to water, it dissolves completely, forming a uniform mixture.
- The alcohol molecules become evenly distributed among the water molecules, resulting in a solution where the composition is the same throughout.
- The individual particles of alcohol cannot be easily separated or distinguished from the water molecules.
- The solution appears as a single phase, without any visible separation or settling of particles.

Other Options:
a) Dust Storm: A dust storm is not a homogeneous mixture because it consists of suspended dust particles in the air. The dust particles are not uniformly distributed and can be easily seen and separated from the air.

b) Suspension of Chalk in Water: A suspension is a heterogeneous mixture where solid particles are dispersed in a liquid but not completely dissolved. In the case of a suspension of chalk in water, the chalk particles do not dissolve but remain suspended in the water. This mixture is not homogeneous because the chalk particles can be seen and will eventually settle down due to gravity.

d) Soap Bubbles: Soap bubbles are formed by blowing air into a soap solution. Although the soap solution appears uniform and transparent, it is actually a foam, which is a type of heterogeneous mixture. Foam consists of gas (air) bubbles dispersed in a liquid (soap solution). The gas bubbles can be easily seen and are not uniformly distributed throughout the mixture.

In summary, a dilute solution of alcohol in water is the only option among the given choices that represents a homogeneous mixture. The other options involve either suspended particles or gas bubbles, making them heterogeneous mixtures.