Three desk shelves-I, II, and III-are being stocked with seven types of food. Bread, Biscuits, Pizzas, Shakes, Cake, Sweet, and Sandwich are to be placed in the shelves so that the goods belonging to any given type are all together in one shelf and no shelf contains more than three types of food. The arrangement of the types of food is subject to the following further constraints: Bread and Cake must be in a shelf together. Neither Biscuits nor Shakes can be in the same shelf as Pizzas. Neither Biscuits nor Shakes can be in the same shelf as Sweet. The Sweet must be in either shelf I or shelf II. Each type of goods must be in some shelf or other. If Bread, Cake, and Sandwich are in I, which of the following must be true?