Answer the following question given this paragraph: 

Like salt water in the ocean, many solutions are normally in the liquid state. However, matter in any state can form a solution. An alloy, which is a mixture of a metal with one or more other substances, is a solid solution at room temperature. For example, the alloy bronze is a solution of copper and tin. Matter in the gaseous state can also form solutions.


Q: An alloy is a mixture of what with one or more other substances?

 Choices:

- acid

- water

- protein

- metal

A:
metal
