Which of the following sauces is traditionally made from egg yolks and oil?

Mayonnaise is traditionally made from egg yolks and oil, along with vinegar or lemon juice and seasoning. The process involves emulsifying the egg yolks with the oil, which creates a thick, creamy texture. This emulsification occurs because the lecithin in the egg yolks acts as a stabilizing agent, allowing the oil and water-based ingredients to blend together smoothly.

Salsa, on the other hand, consists primarily of tomatoes, onions, and peppers rather than any egg or oil-based components. Ranch dressing typically uses buttermilk, sour cream, and various seasonings, which do not include egg yolks as a primary ingredient. Soy sauce is made from fermented soybeans and has a completely different base and preparation method. Therefore, mayonnaise stands out as the correct answer since it is the only sauce listed that relies on egg yolks and oil as its foundational ingredients.