The scatter plot below shows the average trac volume and average vehicle speed on a certain freeway for 50 days in 1999. Which statement best describes the relationship between average trac volume and average vehicle speed shown on the scatter plot? A. As trac volume increases, vehicle speed increases. B. As trac volume increases, vehicle speed decreases. C. As trac volume increases, vehicle speed increases at rst, then decreases. D. As trac volume increases, vehicle speed decreases at rst, then increases.