A train is travelling along a straight track. The graph shows how a quantity $y$ changes with time. Which of the following statements could be true? 1. The train is at rest and $y$ is the distance from the previous station. 2. The train is moving and $y$ is the distance from the previous station. 3. The train is at rest and $y$ is the speed of the train. 4. The train is moving and $y$ is the speed of the train.
- A1 and 2
- B1 and 4
- C2 and 3
- D3 and 4