Concept:Unemployment types are grouped according to their causes, and "factory unemployment" is not a recognised type.Explanation:Structural unemployment occurs when there is a mismatch between workers' skills and available jobs.Frictional unemployment is temporary unemployment while workers are moving from one job to another.Mass unemployment is a term often used to describe large-scale unemployment linked with cyclical unemployment during economic recessions.The term "factory unemployment" has no established meaning in the economic classification of unemployment.Hence, it is not a true type of unemployment.Answer:A. factory unemployment