A rigid, evacuated reaction vessel is filled with \(\text{N}_2\text{(g)}\) and \(\text{H}_2\text{(g)}\) and maintained at a constant temperature. The reaction proceeds according to the following equation:\[\text{N}_2\text{(g)} + 3\,\text{H}_2\text{(g)} \rightleftharpoons 2\,\text{NH}_3\text{(g)}\]The concentrations of all three species are monitored over time, as shown in the graph below. Based on the graph, which of the following correctly identifies the time when chemical equilibrium is first established and provides the correct justification?