Concept:A normal good is defined using the relationship between demand and consumer income.Explanation:A commodity is called normal when an increase in income leads to an increase in demand.Also, a decrease in income leads to a decrease in demand.This means demand and income move in the same direction.In technical terms, such a good has a positive income elasticity of demand, that is, %ΔY%ΔQd>0.Answer:A. income