Concept:A trade debtor is a country whose imports are greater in value than its exports, resulting in trade deficits.Explanation:Less developed nations mainly export cheap raw materials and agricultural products.They import expensive manufactured goods and industrial equipment from industrialized nations.Their import costs therefore exceed their export earnings, causing an unfavourable balance of trade.Thus, they become trade debtors mainly because they import manufactured goods from industrialized nations.Answer:C. They import manufactured goods from industrialized nations.