Use the Information Below to Answer the Following Questions

Multiple Choice

Use the information below to answer the following questions.
Consider the following shortest path problem where node 1 is the starting node and node 6 is the destination node.

-Refer to the figure.What is the constraint associated with node 1?

A) X₂₁+ X₃₁ - X₁₂ - X₁₃ = -1
B) X₂₁ + X₃₁ - X₁₂ - X₁₃ = +1
C) X₂₁ + X₃₁ - X₁₂ - X₁₃ =0
D) X₁₂ + X₁₃ = 0
E) -X₁₂ + X₁₃ = -1