Elasticity from supply curve shapes Steps: - Define elasticity of supply as percentage change in quantity supplied divided by percentage change in price. - Classify curves: vertical (elasticity 0), horizontal (infinite), ray from origin at 45 degrees (unit elastic, constant), steeper than 45 degrees (elasticity <1), flatter (>1). - Examine options: match W to vertical, X to constant elastic (>1, e.g., hyperbolic), Y to 45-degree ray, Z to increasing elasticity curve. - Select option with accurate constant unit elasticity description. Why C is correct: - A supply curve as a straight line from the origin at 45 degrees has constant elasticity of 1, since quantity supplied is proportional to price (Q = kP), so %ΔQ = %ΔP. Why the others are wrong: - A: Vertical curve (W) has elasticity of 0 regardless of price changes, not conditional on rising. - B: Curve X likely has constant elasticity >1 only if hyperbolic (not linear), but option assumes constant without shape confirmation. - D: Curve Z may have elasticity >1, but it varies (not constant) as price rises along non-ray shapes. Final …