Which of the following is a type of emulsification?

Emulsification refers to the process of mixing two immiscible liquids, such as oil and water, into a stable mixture. In the culinary context, a common example of emulsification is the combination of oil and vinegar to create vinaigrettes or sauces like mayonnaise. When properly emulsified, these two liquids blend together smoothly without separating, resulting in a unified and stable mixture that contributes to the desired flavor and texture in dishes.

The combination of oil and vinegar effectively illustrates the concept of emulsification, as it requires the assistance of an emulsifier (such as egg yolks in mayonnaise) to hold the two liquids together. On the other hand, mixing flour and water, stirring sugar into water, and melting butter into a sauce do not involve two immiscible liquids creating a stable blend; instead, they represent different culinary techniques that do not qualify as emulsifications.