What are the basic ingredients of mayonnaise?

The foundational ingredients of mayonnaise primarily consist of egg yolks and oil. The egg yolks serve as an emulsifying agent, which helps to bind the oil and water-based ingredients together to create a stable emulsion. When whisked vigorously, the egg yolks allow for the gradual incorporation of oil, resulting in a creamy and smooth texture that is characteristic of mayonnaise.

Oil is crucial in this mix since it provides the fat component, which is necessary for flavor and richness. While vinegar or lemon juice is often added for acidity and flavor, the essential base of mayonnaise focuses on the combination of egg yolks and oil. This is why the correct answer highlights these two specific ingredients as the primary components of traditional mayonnaise preparation.