Although time consuming, caramelizing onions creates a versatile and tasty addition to one's culinary techniques. Caramelization occurs as the natural sugars in the onion are intensified by the heat as they cook. Yellow onions tend to be sweeter and caramelize better than "sweet onions." Sweet onions are so called because they have fewer sulfur compounds. Be patient and stir often so that the onions do not stick and burn, lowering the heat as needed. It can take up to forty minutes of cooking at a low temperature to achieve the golden brown color needed for such dishes as French onion soup. The aspect of the passage most applicable to other foods is:

A.sulfur compounds.

B.slow cooking.

C.onions.

D.carmelization.