Final answer:
The price elasticity of supply is highest along S1, next highest along S2, and lowest along S3, based on the variance in percentage changes in quantity in response to a standard price change along these curves.
Step-by-step explanation:
The question pertains to the price elasticity of supply along different supply curves. Elasticity measures how much the quantity supplied will respond to a change in price. If we consider price changes moving up the supply curve and measure them in percentage terms, we see that the percentage changes in price decrease as we move from one point to another because of the increasing original price points in each calculation, which in turn increase the denominator of the elasticity formula. This reveals that the supply curve with the steepest slope (S1) would exhibit the highest elasticity, assuming that larger percentage changes in quantity correspond to each $1.50 increase in price, while the least steep curve (S3) would show the lowest elasticity since the same $1.50 leads to smaller percentage changes in quantity supplied. Therefore, the correct answer to the student's question would be that the price elasticity of supply is highest along S1, next highest along S2, and lowest along S3.