In Modeling a Traveling Salesman Problem, Let $X_{i j k}$ Be a 0-1 Decision Variable, Which Takes a Value of Be

In modeling a traveling salesman problem, let $X_{i j k}$ be a 0-1 decision variable, which takes a value of 0 if in the kth leg the tour corresponding to the solution does not go from node $\mathrm{i}$ to node $\mathrm{j}$ . $\mathrm{X}_{\mathrm{ijk}}$ is set to be equal to 1 if the tour goes from node $\mathrm{i}$ to node $\mathrm{j}$ in the kth leg. In a problem with just 4 nodes and without loss of generality, assume that the tour starts and ends in node 1 . If, in a particular solution, $X_{213}=1$ , it means that the tour corresponding to the solution

A) goes from node 3 to 1 in the 2nd leg
B) goes from node 2 to 1 in the 3rd leg
C) goes from node 1 to 2 in the 3rd leg
D) goes from node 1 to 3 in the 2 nd leg