The Tunnel

**Scenario.** 45 minutes in, you have one structural idea left untested on problem 2, and problem 4 (worth the same) you can solve in 20. The decision tree says: **Which approach is the best fit? The program only needs to print the letter.** **A)** Finish problem 2's idea — sunk cost means you should not waste the investment **B)** Switch to problem 4: bank the certain solve, then return to 2 with the remaining time **C)** Skip both and read the statements again **D)** Optimize problem 1's solution further