Problem 4 (15 points) NASA intends to contract three special valves for its space shuttle program. Four bids have been received, and, according to government restrictions, no contractor may be permitted to produce more than one valve type. The bids, in terms of ($1000) per valve type, and the potential subcontractor information are given below. Use the Hungarian algorithm to determine the contractor each valve type should be assigned to so that the procurement cost is minimized. If exist, display all alternative optimal solutions. For each solution, write the assignment of each valve type to a contractor and the total procurement cost. A 16 18 Valve type Contractor 1 Contractor 2 Contractor 3 Contractor 4 12 B 23 20 C 10 11 201 10 20 18 14 10