Option 2: 0.5 -> Price elasticity of demand is calculated as (% change in quantity demanded) / (% change in price). Here: % change in quantity = [(12-15)/15] × 100 = -20%, and % change in price = [(7-5)/5] × 100 = 40%. Therefore, elasticity = -20% / 40% = -0.5. The absolute value is 0.5, indicating inelastic demand (less than 1) where quantity demanded changes proportionally less than price changes. -> correct