Explanation:

- Option 1: Uniform

- If elasticity is uniform, demand responds similarly across all markets. This limits the effectiveness of price discrimination because consumers would react to price changes in the same way.

- Option 2: Different

- *Correct Answer*

- When elasticity differs, firms can charge higher prices where demand is inelastic and lower prices where it's elastic, maximizing profits. This is the essence of price discrimination.

- Option 3: Less

- Less elastic demands mean consumers do not respond significantly to price changes, but it doesn't address the condition for profitability across submarkets.

- Option 4: Zero

- Zero elasticity implies absolutely no response to price changes. While able to set any price, it doesn’t help with differential pricing across markets.