Two Keys, One Order

**Scenario.** Jobs (t_i, d_i): process all; minimize the maximum of (finish time − deadline). Which sort key has a correct exchange proof? **Which approach is the best fit? The program only needs to print the letter.** **A)** Shortest processing time first **B)** Earliest deadline first (swap-adjacent exchange shows EDS never worsens max lateness) **C)** Largest deadline first **D)** Any order works — max lateness is order-independent