Which statement BEST explains whether or not Robert’s graph represents a proportional relationship? A The graph does not represent a proportional relationship because the rate of miles per hour is always increasing. B The graph represents a proportional relationship because the rate of miles per hour is always decreasing. C The graph does not represent a proportional relationship because it is not a horizontal line showing the same number of miles traveled each hour. D The graph represents a proportional relationship because the rate of miles per hour is the same at each point.