A car moves along the positive x–axis. During a certain interval its velocity–time graph lies above the time axis but has a negative slope. What does this indicate about the car’s motion in that interval?
(a) It is speeding up in the positive direction.
(b) It is moving in the negative direction with increasing speed.
(c) It is slowing down in the positive direction.
(d) It is moving in the positive direction with constant speed.