Which of the following is an example of emulsion?

The correct answer is option 1. Milk.

An emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable). Among the options provided, milk (option 1) is an example of an emulsion. Milk is a mixture of water and fat globules dispersed throughout the water phase.

So, the correct answer is 1. Milk.