Answer : The correct option is, mixture.
Explanation :
Pure substance : It is defined as a substance that is made by the combination of only one type of atom or only one type of molecule. The pure substance can not be separated by simple physical methods.
Compound : It is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.
The constituents of compound can not be separated into simpler substances by physical methods. They can be separated by chemical methods. A compound can not retains the physical properties of its constituent elements.
Element : It is a pure substance which is composed of atoms of similar elements.
Mixture : It is defined as the substance that is made by the combination of two or more different components. Or, we can say that it is created when solids liquids or gases mixed with one another.
Hence, the correct option is, mixture.