Four claims are listed below. If you think it is false: either disprove it or give a counter example.
A) Shortest path problem is an NP-Hard problem.
B) Travelling Salesman Problem can be solved in polynomial time with an enumeration (or exhaustive) algorithm.
C) Dijkstra's Algorithm guarantees an optimal solution for any given graph with negative edges.
D) 2-center facility location problem cannot be solved in polynomial time. E) Union of two non-convex sets cannot be convex.
