A train mans first 75 km at a certain uniform speed and next 90 km at an average speed of 10 km/h more than the normal speed. If it takes 3 hours to complete the journey, then how much timewill the train take to cover 300 km with normal speed?

A

5 hours 15 minutes

B

5 hours 25 minutes

C

5 hours

D

6 hours