To allow a train to halt safely, it always passes a signal with a yellow light before it encounters a signal with a red light. At the yellow light, drivers apply the brake, causing a steady deceleration so that the train stops exactly at the red light. The separation between the red and yellow lights is $x$. If the train's speed is raised by $20\%$, while its deceleration remains unchanged, what is the least possible distance between the lights?
- A$1.20x$
- B$1.25x$
- C$1.44x$
- D$1.56x$