3. Solving Assignment Problem. (Each person should finish one task, and each task should be finished by only one task, and all the tasks should be finished. Calculate the minimum total time spent by the four persons.) (20) Table 1. The time spent by each person to finish each task Person A B D Task I 21 25 16 23 II 17 21 18 19 19 15 16 IV 19 16 15 16