A train meets with an accident 30 minutes after starting from station A. If it covers rest 7/8th of the distance i.e. 210 km with its usual speed, it is delayed by 30 minutes. In order to reach on time i.e. the time it should have reached had the train not met with the accident, then what should be the increase in speed of the train?

• A. 30 kmph
• B. 12 kmph
• C. 12.5 kmph
• D. 7.5 kmph
• E. 10 kmph