Answer:
A. Add sand
Explanation:
A mixture in which particles are not uniformly distributed throughout the solution then it is known as a heterogeneous mixture.For example, sand in water is a heterogeneous mixture.Where as a mixture in which particles are evenly distributed throughout the solution then it is known as a homogeneous solution.For example, salt in water is a homogeneous solution. This, is why we can conclude that to make salt water a heterogeneous mixture, you would have to add sand.
Hopefully this answers your question.
