Below is the linear programming for the Shortest Path Problem. Considering the second contraint in the mathematical model :
∑ixji−∑ixij=0∀j≠s, j≠t
What is the logic behind this contraint?
A. To make sure there is only one solution
B. To make sure that the path is connected between the nodes
C. To make sure the variable stays binary
D. This contraint is redundant and not necessary