Final answer:
Solid butter is a heterogeneous mixture because it is made up of different components that are not uniformly distributed.
Step-by-step explanation:
The correct answer to this question is (c) solid butter. Solid butter is a heterogeneous mixture because it is made up of different components that are not uniformly distributed. When you look at a stick of butter, you can see regions of different compositions, such as the creamy part and the harder part. Therefore, solid butter is an example of a heterogeneous mixture.