Could you please help me to answer #4 D and E

4. (total 20 points) This problem is concerned with finding the shortest path from s to t in the following network, where the number on each arc is the length of that arc: 8 2 3 4 S 3 7 20. to Pd). (5 points) Using the results you obtained in (a), let 7; be the length of a shortest path from s to i, for each node i. Verify that 7* is feasible for D. Show that in fact x* is optimal for P and n*is optimal for D. 15 1 solution PHS O a single e). (5 points) The following statement follows from the constraints of D: For any arc 2 -+ j in the network, the shortest path from s to j is