Concept:Price elasticity of demand measures how quantity demanded responds to a price change.It is calculated as: % change in price% change in quantity demanded.Explanation:Old price =N120, new price =N80.Change in price =120−80=40.% change in price=12040×100=33.33%.Old quantity =300, new quantity =500.Change in quantity =500−300=200.% change in quantity demanded=300200×100=66.67%.Elasticity of demand =33.33%66.67%=2.0.Using absolute values, the elasticity is 2.0.Answer:D. 2.0