The Unlabeled Wall

**Scenario.** A problem gives n ≤ 100000 intervals and asks for the largest set of pairwise non-overlapping ones. The statement mentions no algorithm. First move? **Which approach is the best fit? The program only needs to print the letter.** **A)** Try DP over all subsets **B)** Model it (intervals, objective = max compatible set), note n ≤ 10^5 admits O(n log n), then hunt for the exchange-argument sort key **C)** Brute force with pruning **D)** Random restarts with different orders