Final answer:
The information provided does not mention any particular system that Benny used for picking food in the cafeteria, instead focusing on stories from Bibi and an excerpt mentioning Mrs. Peters having bread set.
Step-by-step explanation:
Based on the information provided, there is no specific system that Benny had for picking food in the cafeteria mentioned. The text revolves around Bibi, who is preparing food and recounting personal stories, but it does not provide details about Benny's food selection system. Similarly, the excerpt from Mrs. Peters simply states she had a bread set, without any reference to Benny or his methods for selecting food. Thus, without additional context, a system for Benny to choose cafeteria food cannot be described.