A goods train moves past a station at a steady speed of $10\,\text{m s}^{-1}$ at time $t = 0$. An express train is stationary at the station. Exactly when the goods train passes, the express train starts from the station with a constant acceleration of $0.5\,\text{m s}^{-2}$. The two trains travel in the same direction along straight, parallel tracks. At what time $t$ does the express train catch up with the goods train?
- A$6\,\text{s}$
- B$10\,\text{s}$
- C$20\,\text{s}$
- D$40\,\text{s}$