Which of the following is an example of a mixture?

The correct choice is olive oil, which is an example of a mixture. Olive oil is composed of various fatty acids and other compounds, making it not a pure substance but a combination of different elements. Mixtures consist of two or more different substances that maintain their individual properties and can often be separated by physical means. In the case of olive oil, the various components work together to create a unique flavor and texture but do not undergo a chemical change, ensuring that the original substances can be identified within the mixture.

On the other hand, hydrogen, sodium chloride, and oxygen are all considered pure substances. Hydrogen and oxygen are elements, meaning they cannot be broken down into simpler substances. Sodium chloride, commonly known as table salt, is a compound, which is a substance formed when two or more elements chemically bond together in a fixed ratio, resulting in a material with different properties from those of the individual elements.