Option 1: 0.4 -> Price Elasticity of Supply (PES) = (% change in quantity supplied) / (% change in price). Here, % change in quantity supplied = 20%. % change in price = [(15-10)/10] × 100 = 50%. Therefore, PES = 20%/50% = 0.4. This indicates inelastic supply, meaning supply is relatively less responsive to price changes. -> correct