Is the psychological desire to eat specific foods and is the physiological sensation that encourages us to seek out food?

The answer is hunger.  Psychological hunger is produced by a wish to eat either out of custom, because you see good food everywhere you, because you are expressive or upset, or since it tastes good. We contend that obesity is not produced by physiological hunger, the virtuously physical consumption of high-calorie meals at fast food eateries, or eating disproportionately when you are full. As an alternative, hunger has psychological reasons, and we frequently feel hungry even with full stomachs.

i would say b. research typically uses a variety of sources