13. Answer this question based upon the TRANSPORTATION PROBLEM below.

Which of the following is true?

Group of answer choices

A. The problem has 9 decision variables.

B. The problem has 3 decision variables

C. The problem has 12 decision variables

D. The problem has 6 decision variables

The Transportation Problem: Wheat is harvested in the Midwest and stored in grain elevators in three different cities, Kansas city, Omaha and Des Moines. These grain elevators supply flour mills located in three cities, Chicago, St. Louis and Cincinnati. Grain is shipped to the mills in railroad cars. Each car is capable of holding 1 ton of wheat. Solve a transportation problem based upon the following data: Grain Elevator 1. Kansas city 2. Omaha 3. Des Moines SUPPLY AVAILABLE 150 175 275 Each mill has the following demand profile every month: MILL Chicago St. Louis Cincinnati DEMAND 200 100 300 The transportation cost per ton from each supply node to each demand node is given below: Kansas city Omaha Des Moines Chicago $6 7 4 St. Louis $8 11 5 Cincinnati $10 11 12