Concept:Cockroaches are household pests that contaminate food and spread diseases, causing economic losses.Explanation:Cockroaches crawl over food and kitchen surfaces, carrying harmful microorganisms on their legs and bodies.They contaminate food and utensils, leading to the transmission of diseases such as food poisoning and gastroenteritis.This contamination results in spoiled food, increased medical expenses, and reduced productivity.Therefore, disease transmission through food contamination is an economic importance of cockroaches.Answer:B. cockroaches