Final answer:
The additional information needed to determine the state of the sample is whether the sample has a fixed shape. If the sample has a fixed shape, it is a solid. If the sample does not have a fixed shape, it could be a liquid or a gas.
Step-by-step explanation:
The additional information needed to determine the state of the sample is C. whether the sample has a fixed shape. Knowing whether the sample has a fixed shape is important because it distinguishes between the states of matter. If the sample has a fixed shape, it is a solid. If the sample does not have a fixed shape, it could be a liquid or a gas. For example, water has a fixed volume (it takes the shape of the container), but it does not have a fixed shape (it can be poured into different containers).