The relationship between traffic flow rate (q) and density (D) is shown in the figure
The shock wave condition is depicted by
(A) flow with respect to point $1\left(q_{1}=q_{\max }\right)$
(B) flow changing from point 2 to point $6\left(\mathrm{q}_{2}>\mathrm{q}_{6}\right)$
(C) flow changing from point 3 to point $7\left(\mathrm{q}_{3}<\mathrm{q} 7\right)$
(D) flow with respect to point 4 and point $5\left(\mathrm{q}_{4}=\mathrm{q} 5\right)$
The relationship between traffic flow rate (q) and density (D) is shown in the figure
The shock wave condition is depicted by
(A) flow with respect to point $1\left(q_{1}=q_{\max }\right)$
(B) flow changing from point 2 to point $6\left(\mathrm{q}_{2}>\mathrm{q}_{6}\right)$
(C) flow changing from point 3 to point $7\left(\mathrm{q}_{3}<\mathrm{q} 7\right)$
(D) flow with respect to point 4 and point $5\left(\mathrm{q}_{4}=\mathrm{q} 5\right)$
flow changing from point 2 to point $6\left(\mathrm{q}_{2}>\mathrm{q}_{6}\right)$