A subway train is traveling at \( 80 \text{ km h}^{-1} \) when it approaches a slower train \( 50 \text{ m} \) ahead traveling in the same direction at \( 25 \text{ km h}^{-1} \) . If the faster train begins decelerating at \( 2.1 \text{ ms}^{-2} \) while the slower train continues at constant speed, how soon and at what relative speed will they collide?

A \( 9.58 \text{ s} \) and \( 4.8 \text{ ms}^{-1} \)

B \( 4.97 \text{ s} \) and \( 4.8 \text{ ms}^{-1} \)

C \( 9.58 \text{ s} \) and \( 11.8 \text{ ms}^{-1} \)

D \( 4.97 \text{ s} \) and \( 11.8 \text{ ms}^{-1} \)

Correct Answer: Option D